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Non-HA Filler Lumps Under The Eye —
Managed, Not Dissolved

Atelier Aesthetics · Medical Director: Dr. Sin Yong · Updated 23 Oct 2026

Collagen-stimulating fillers such as PLLA, CaHA, PCL and PDLLA are not hyaluronic acid, so hyaluronidase cannot dissolve a lump they leave under the eye. This page explains why these lumps behave differently, how Dr Sin Yong identifies the material at Atelier, and the options that remain when dissolving is not one of them.

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The Mechanism

Why The Enzyme Has Nothing To Act On

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Hyaluronidase is an enzyme with one target: hyaluronic acid. Poly-L-lactic acid (PLLA), calcium hydroxylapatite (CaHA) and polycaprolactone (PCL) are different materials, and it has no effect on them. The same applies to poly-D,L-lactic acid (PDLLA). Where PDLLA sits in a hyaluronic acid carrier, only the carrier can be dissolved.

These products work by provoking collagen around their particles over months, so a lump can be firm, and it can appear or change well after the injection.

Reason One
A Different Material
The enzyme that reverses hyaluronic acid filler cannot break down a collagen stimulator, so dissolving is not an option for the stimulator itself.
Reason Two
Collagen Around Particles
Where particles cluster, the collagen the body lays down around them forms a firm lump.
Reason Three
Thin, Moving Skin
Lid skin is thin and the muscle beneath it is never still, so even a small cluster shows and can be felt. In a published paper covering 5,081 CaHA treatments, almost half of the adverse events (49%) were in areas that move a lot, such as around the eyes and mouth.
Reason Four
More Than One Product
Under-eyes treated over several years have often had more than one product, so hyaluronic acid can lie layered beside a stimulator.

Types

Which Material Is In The Lump

A non-HA lump is often mistaken for a hyaluronic acid one, but it does not soften with hyaluronidase, so the product history largely decides the diagnosis. The material also changes the route. Patients often know these products by brand: PLLA as Sculptra, CaHA as Radiesse, PCL as Ellanse, and PDLLA in a hyaluronic acid carrier as Juvelook.

Specifications

Region
Tear trough and lower eyelid, often after treatment elsewhere
Assessment
Product history (what, when and how much), then examination at rest and in expression
Modalities
Time; injected medication after diagnosis; Time Freeze Laser LCLR considered case by case; surgical excision by referral, as a last resort
Review
Any hyaluronic acid component dissolved first, then the stimulator reassessed
Type I
PLLA
Clustered particles with a collagen response, or product that has spread. Early soft papules may settle with time and massage; a persistent lump is treated only after diagnosis.
Type II
CaHA
Calcium-based microspheres that show clearly on imaging. Most CaHA nodules in the large published paper resolved; persistent ones are managed by what is found.
Type III
PCL
Microspheres that leave a firm deposit with a collagen response around it. Hyaluronidase does nothing here, so management relies on the other routes.
Type IV
PDLLA Or Layered HA
Where a stimulator sits in, or beside, hyaluronic acid, only the HA part dissolves. That part is dissolved first and the stimulator reassessed after.

The Decision

Identify First, Then Manage

At Atelier, tear trough filler is a low G-prime hyaluronic acid, which hyaluronidase can reverse; see tear trough refinement. Collagen stimulators are planned for broader volume loss and skin quality, as set out on collagen biostimulators, with hyaluronic acid preferred for the tear trough. A non-HA lump under the eye is therefore usually seen when someone comes for an assessment after treatment elsewhere.

Dr SY first asks which product was used, when, and in what amount, then looks at the area both at rest and in movement.

When to wait. Most CaHA nodules in that large published paper resolved, and small early PLLA papules may soften with time and massage. Lumps after PLLA are covered in more detail on PLLA nodules.

When to treat. For persistent nodules and granulomas, published options include corticosteroid injected into the lump, often combined with 5-fluorouracil to limit thinning of the skin. This follows a diagnosis, never a guess. For some PCL nodules, excess PDLLA, layered hyaluronic acid or PLLA that has moved, Dr SY may consider Time Freeze Laser LCLR, including under the eye. It is not a routine step, and whether it suits a particular eye is decided at assessment.

As a last resort. Surgical excision, arranged by referral where it is needed, is kept for a nodule that has not responded to anything else, and it leaves a scar of its own. A nodule that is inflamed or infected is treated medically first, before any of these.

Hyaluronic acid in the mix. Any HA component can still be dissolved, in stages, as on filler correction. Product that has spread beyond where it was placed shows the patterns on filler migration signs.

Collagen Biostimulators

Safety

Warning signs: when to get help now

A firm lump from a collagen stimulator can usually wait for a planned assessment. These signs cannot, whatever the filler.

  1. Vision change or eye pain after filler: call 995 or go to an emergency department immediately, and contact the injecting doctor. Go directly: do not travel to the clinic first, and do not drive yourself.
  2. Pale, dusky or mottled skin, or worsening pain: urgent assessment now; do not wait. Contact the clinic that injected you straight away; if you cannot reach it, go to A&E. These can be signs of filler in a blood vessel. Give the product name, because non-HA material cannot be dissolved. See vascular occlusion warning signs.
  3. A lump that turns hot, red and tender, with or without fever: it needs prompt review by a doctor and is managed medically first. Do not massage it.
  4. A firm lump without these signs: book an assessment. Do not add more filler to hide it.

FAQ

Non-HA Filler Lumps — Common Questions

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It matters a great deal. A lump from PLLA, CaHA, PCL or PDLLA does not soften with hyaluronidase and is often mistaken for hyaluronic acid, so the product history largely decides the diagnosis and the route. Ask the clinic that treated you for the product name, the dates and the amount used, and bring whatever you can to your assessment with Dr SY.
Many do. In a published paper covering 5,081 CaHA treatments, 3% led to an adverse event; 96% of those were nodules, and most resolved. The figures are not specific to the under-eye, but they make waiting a reasonable first option for a quiet lump. A nodule that persists, or one that becomes red, hot or tender, needs assessment rather than more waiting.
Partly. Some PDLLA products are suspended in a hyaluronic acid carrier, and hyaluronidase can dissolve that HA part but not the PDLLA. Any excess PDLLA is then managed as a collagen stimulator. The same logic applies when hyaluronic acid has been layered beside another stimulator: the HA is dissolved first, and the remaining material is reassessed afterwards.
Sometimes. For some PCL nodules, excess PDLLA, layered hyaluronic acid or PLLA that has moved, Dr SY may consider Time Freeze Laser LCLR, which is offered at Atelier, and this can include the under-eye. It is not a routine step: the material is identified first, a nodule that is inflamed or infected is managed medically before anything else, and whether the laser suits your eye is decided at assessment.
Surgery is possible but kept as a last resort, for a nodule that has not responded to anything else, and it leaves a scar of its own. Where it is needed, it is arranged by referral. Before that, the options are time, injections chosen after a diagnosis, and other routes such as Time Freeze Laser LCLR where it suits. Which of these applies depends on the material and how the lump behaves.
PLLA and CaHA usually persist for up to about two years, occasionally longer, and their particles are broken down slowly, over a year or more. A lump made of them cannot be reversed the way hyaluronic acid can: a misplaced or overdone stimulator has to be waited out or managed, sometimes over a year. That is one reason these products are used with restraint.

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Related at Atelier

Related
Collagen Biostimulators
PLLA and CaHA as planned treatments, and why restraint governs the dose.
Related
Filler Correction
Dissolving the hyaluronic acid part first, in stages, before anything else.
Related
Filler Migration Signs
How product that has spread from where it was placed tends to look.

References

  1. Kadouch JA. J Cosmet Dermatol. 2017;16(2):152-161.
  2. Wollina U, Goldman A. J Cutan Aesthet Surg. 2024;17(4):273-281.
  3. Vleggaar D, Fitzgerald R, Lorenc ZP. J Drugs Dermatol. 2014;13(4 Suppl):s35-39.
  4. Lemperle G, Gauthier-Hazan N. Plast Reconstr Surg. 2009;123(6):1864-1873.
  5. Ministry of Health, Singapore
  6. HealthHub, Singapore — public health information

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