Fibrotic filler lumps: firm scar-tissue nodules after filler, and what can help

What are fibrotic filler lumps?

Fibrotic filler lumps are firm nodules made largely of scar-like (fibrous) tissue that the body has laid down in or around filler, rather than of soft filler gel alone. They are uncommon, and most filler treatments go smoothly. When they do occur, they tend to feel cool, firm and well defined, without the pain, tenderness or redness of an inflamed lump, which is why many people first notice them as a hard lump after filler that is still there months later.

Fibrous tissue is the body's ordinary repair material, made mainly of collagen fibres. After filler, it can build up in a few broad situations:

• Around collagen-stimulating fillers: materials such as poly-L-lactic acid and calcium hydroxylapatite are designed to prompt new collagen, and nodules are a recognised complication of these particle-based fillers.
• After a long-running reaction: a delayed inflammatory reaction, a granuloma or an infection can leave firm tissue behind. In a published case of recurring nodules after hyaluronic acid filler, a tissue sample showed fibrosis alongside chronic inflammation and remaining filler (Orseth and colleagues, 2018).
• After needle work on a lump: guidance on delayed nodules cautions that releasing a firm nodule with a needle can itself cause further fibrosis or scarring (King and colleagues, 2016).

"Fibrotic" describes what a lump is made of, not what caused it, so the cause still has to be worked out before anything is treated. This guide covers firm, scar-tissue lumps specifically. For every kind of lump after filler, start with our guide to filler lumps and nodules, and for how SkinRev Lab approaches filler problems overall, see filler correction at SkinRev Lab.

How do fibrotic nodules differ from other filler lumps?

Fibrotic nodules differ from other filler lumps mainly in what is inside them: firm scar-like tissue rather than soft gel, active inflammation or infection, and that changes what can help. Doctors first sort lumps into non-inflamed and inflamed, because the two are managed differently: non-inflamed lumps are usually cool, firm and well defined, while inflamed ones are painful, tender or red (King and colleagues, 2016).

These features overlap, and one lump can be part gel, part fibrous tissue and part inflammation. That is why a firm lump is examined, and often scanned, before anything is injected into it. For the other lump types in detail, see filler granulomas and delayed nodules, filler infection and biofilm and filler migration.

Why do fibrotic nodules form after filler?

Fibrotic nodules form after filler when the body's repair response lays down more collagen fibres than intended in one spot, for example around a collagen-stimulating product, after a long-running inflammatory reaction or after needle work on a lump.

Collagen-stimulating fillers. These are meant to trigger collagen. A review of how fillers break down describes calcium hydroxylapatite microspheres as thought to stimulate collagen production by activating fibroblasts, the cells that make collagen, and describes lactic acid fillers as breaking down slowly by absorbing water, with long-lasting fillers of this kind usually persisting for up to about two years (Wollina and Goldman, 2024). Guidance on delayed nodules advises against placing filler too superficially and notes that injecting highly mobile areas such as the lips raises the risk of non-inflamed nodules (King and colleagues, 2016).

Hyaluronic acid fillers. These are not designed to stimulate collagen. Fibrosis can still develop when a lump has been inflamed for a long time, as in the case report above, where the tissue showed fibrosis as well as remaining filler (Orseth and colleagues, 2018).

Granulomas. Some granulomas contain marked fibrous tissue. A 2024 review notes that granulomas with conspicuous fibrosis may not respond to the dissolving enzyme (Kroumpouzos and Treacy, 2024).

Most people who have filler never develop any of these. Where one does appear, the history of what was injected, where and when is the most useful starting point.

Sculptra and Radiesse nodules: lumps after collagen stimulators

Sculptra and Radiesse nodules are firm lumps that can form after these collagen-stimulating fillers, and they cannot be dissolved with the enzyme used for hyaluronic acid filler. Sculptra is made of poly-L-lactic acid; Radiesse is calcium hydroxylapatite in a gel. A 2024 review lists both materials among fillers that cannot be dissolved by hyaluronidase (Kroumpouzos and Treacy, 2024).

• Small bumps and firmer nodules: guidance on delayed nodules notes a comparatively high frequency of granulomatous nodules after poly-L-lactic acid, up to 14 months or more after injection, and that injecting highly mobile areas such as the lips raises the risk of non-inflamed nodules (King and colleagues, 2016).
• Red, tender or growing lumps months later: these are assessed as a possible reaction or infection, not assumed to be fibrosis.

A 2025 guideline on nodules after poly-D,L-lactic acid, a related but different collagen stimulator (not poly-L-lactic acid), describes non-inflamed nodules as coming from build-up or uneven spread of product, notes that they lack obvious signs of inflammation and respond poorly to the medicines used for inflamed lumps, and states that they do not respond to straightforward enzyme treatment (Magacho-Vieira and Ducati, 2025).

At SkinRev Lab, Dr Sin Yong assesses lumps after collagen biostimulators as well as after hyaluronic acid filler, with a plan decided at consultation. For product detail, see Sculptra and its nodules, Radiesse and why it cannot be dissolved and non-dissolvable filler removal. Collagen fillers are a different product type, covered in collagen injection complications.

Hard lump after filler months later: what could it be?

A hard lump after filler that appears or persists months later can be leftover filler, a delayed inflammatory nodule, a granuloma, a late infection linked to biofilm or a fibrotic nodule, and these cannot be told apart reliably by touch alone. Timing gives the first clue. Published guidance links a lump present at the time of injection or within hours to placement or swelling, inflamed swelling that starts between about 3 days and 2 weeks to likely infection, delayed nodules to weeks or months later, and foreign body granulomas to several months to years (King and colleagues, 2016).

Clues that point towards fibrosis:

• The lump is cool, firm, well defined and not tender.
• It has stayed much the same size for months.
• The skin over it is a normal colour and is not warm.
• It did not change, or only partly shrank, after dissolving.
• It sits where a collagen stimulator was injected.

Clues that point elsewhere: tenderness, redness, warmth, several treated areas swelling together, or a soft, fluid feel. These suggest a reaction or infection and need assessment first. Our guide to filler problems years later covers late swelling and old filler, and filler swelling covers the early weeks.

Go to an emergency department now if the skin turns pale, dusky or mottled, pain is severe or rising, your vision changes, or redness is spreading with fever. Skin colour change and rising pain can signal filler vascular occlusion. For any change in vision, call 995. Do not massage, squeeze or press a firm lump unless your doctor advises it.

Can hyaluronidase dissolve fibrotic filler lumps?

No: an enzyme (hyaluronidase) dissolves hyaluronic acid filler, but it does not dissolve collagen-stimulating fillers such as poly-L-lactic acid or calcium hydroxylapatite, and it is not expected to remove established fibrous tissue. A 2024 review of the enzyme lists poly-L-lactic acid, calcium hydroxylapatite and polymethylmethacrylate among fillers that cannot be dissolved by it, and notes that granulomas with conspicuous fibrosis may not respond (Kroumpouzos and Treacy, 2024).

The reason is chemistry. The enzyme works by cutting a specific bond in the sugar chains of hyaluronic acid (Wollina and Goldman, 2024). Scar tissue is built from collagen fibres, which are proteins, so the enzyme is not designed to break it down. A 2025 guideline on nodules after poly-D,L-lactic acid, a related but different filler, likewise states that they do not respond to straightforward enzyme treatment (Magacho-Vieira and Ducati, 2025).

Where the enzyme can still play a part:

• Mixed lumps: if hyaluronic acid gel is still trapped inside or beside the fibrous tissue, dissolving it can reduce the lump, though firm tissue may remain. In the case report of recurring nodules after hyaluronic acid filler, the enzyme reduced a nodule at first, but it persisted and further treatment was needed (Orseth and colleagues, 2018).
• Precise placement: the same 2024 review notes that injecting under high-frequency ultrasound guidance can increase the likelihood that a nodule or granuloma responds (Kroumpouzos and Treacy, 2024).

Repeated enzyme injections into a lump that holds no hyaluronic acid add the enzyme's own side effects without benefit. See dissolving filler with hyaluronidase, how long filler takes to dissolve and hyaluronidase side effects.

How a doctor assesses a firm lump after filler

A doctor assesses a firm lump after filler by taking a full filler history, examining the lump and, where useful, scanning it with high-frequency ultrasound to see whether filler is still present, what it looks like and how deep it sits. The aim is to answer three questions before treating: is this filler, inflammation, infection or the person's own tissue; is hyaluronic acid present; and is anything urgent.

1. History: which products were injected, when, where and how much; any dissolving before; recent illness, dental work or vaccination; and allergies, including bee or wasp sting allergy.
2. Examination: size, firmness, tenderness, warmth, skin colour, whether the lump moves, and how it looks at rest and with expression, with dated photographs.
3. Ultrasound mapping: a 2024 review describes high-frequency ultrasound as a first-line tool to identify filler (Kroumpouzos and Treacy, 2024).
4. Tests when needed: if infection is suspected, a sample may be sent for testing, and a tissue sample (biopsy) can confirm what a nodule contains. Ultrasound is useful especially when a biopsy is not desirable (DermNet).

The answer decides the plan: dissolving if hyaluronic acid is present, treating infection first if suspected, and otherwise options aimed at the fibrous tissue itself, or waiting. Read more about ultrasound-guided filler dissolving, or watch the short ultrasound filler mapping video.

What can help fibrotic filler nodules?

Fibrotic filler nodules are usually managed step by step, starting with observation for small lumps that are not painful and moving to treatment by a doctor when a nodule is visible, bothersome or growing; no single treatment suits every case, and some firm tissue may remain. Your doctor will advise which, if any, suits you.

• Time and dated photos: collagen-stimulator particles break down slowly (Wollina and Goldman, 2024), and guidance notes that some lumps that can be felt but not seen may simply be watched (King and colleagues, 2016). Photos in the same light help show change.
• Dissolving any hyaluronic acid component: with an enzyme (hyaluronidase), placed under ultrasound where useful.
• Medicine injected into the nodule: small, measured amounts can soften firm or inflamed tissue, sometimes over several sessions. Guidance notes this can thin the skin above or cause small visible blood vessels, so treatment starts at a low strength (King and colleagues, 2016).
• Medicines prescribed by the doctor: used when inflammation or infection is part of the picture, and before other steps if infection is suspected.
• Breaking up or releasing the nodule: a doctor may break up a non-inflamed nodule with a fine needle and sterile fluid, or release it under the skin, with care because this can add further fibrosis (King and colleagues, 2016). For nodules after poly-D,L-lactic acid, a related but different filler, one guideline proposes vigorous massage as a first step (Magacho-Vieira and Ducati, 2025); do not do this yourself unless advised.
• Surgical removal: for a discrete nodule that persists despite other steps, a plastic surgeon's opinion is sought.

Fibrotic filler lumps at SkinRev Lab: how Dr Sin Yong assesses them

At SkinRev Lab, fibrotic filler lumps are assessed and treated by Dr Sin Yong, medical adviser, who examines the lump, maps it with ultrasound where useful and explains the options, including waiting; assessment and treatment are priced at consultation. SkinRev Lab is at #B1-28 CityLink Mall, by City Hall MRT, open daily 11am to 8pm.

What to bring:

• The names of the products injected, if known, and whether each was hyaluronic acid or a collagen stimulator.
• Dates, areas and amounts, and any earlier dissolving.
• Dated photos showing when the lump appeared and how it has changed.
• A list of your medicines and allergies, including bee or wasp sting allergy.

What Dr Sin Yong checks first: urgent signs, signs of infection or active inflammation, and whether hyaluronic acid is present on the scan. If a lump is not hyaluronic acid, he does not inject the dissolving enzyme into it, and if infection is suspected, that is addressed before anything else. He may advise leaving a small, stable lump alone, and he refers for a surgical opinion where that is the better route.

If you were treated elsewhere and would like an independent view first, our guide to a filler second opinion explains what to bring. Dr Sin Yong's background is on the medical adviser page.

How to lower the risk of fibrotic nodules after filler

The risk of fibrotic nodules after filler is lowered mainly by knowing what is being injected, choosing a material that suits the area and having it placed and dosed with care by a doctor who can manage problems. Most treatments go smoothly, and these questions help you plan for the uncommon ones.

Questions to ask before treatment:

• What exactly is the product, and is it hyaluronic acid, a collagen stimulator or something else?
• Can it be dissolved if there is a problem, and if not, what is the plan for a lump?
• For a collagen stimulator, how is it mixed and how deep will it be placed?
• Is this product suited to thin or very mobile areas such as the lips and under the eyes?
• Will you scan for old filler first, and how many sessions are planned, with what spacing?
• Who reviews me, and how do I reach the doctor, if a lump appears months later?

After treatment: follow the aftercare you are given, keep the product name and date, and have any firm lump that is still present after a few weeks reviewed rather than pressing on it yourself. Seek care promptly for any lump that becomes red, warm or painful. For the full range of filler problems, see filler problems and the filler complications glossary.