A Brazilian butt lift (BBL) is two procedures in one: liposuction to harvest fat, usually from the waist, back or thighs, and fat transfer into the buttocks. Unevenness can appear at either end. Each kind has a different cause and a different answer, and some of it simply needs time.
Short answerSwelling makes most BBL results look uneven for the first months. Unevenness that remains after that can come from uneven graft survival, a lump of fat necrosis, a dent or ripple at the liposuction site, or skin that did not retract. Superficial excess and loose skin can be treated from the surface; dents and large asymmetries are surgical questions for your surgeon.
Key facts
Two sites
Donor areas (liposuction) and the buttocks (fat transfer)
Early weeks
Swelling and uneven settling are expected
Graft side
Uneven survival, asymmetry, lumps from fat necrosis or oil cysts
After a BBL, the buttocks are swollen and some of the transferred fat will not survive. How much survives differs from one side to the other, which is why early asymmetry is common and often changes. The donor areas are bruised and swollen too, and ridges under compression garments can make the surface look uneven for weeks.
Most surgeons judge the result only once swelling has settled, typically several months after surgery. Judging earlier risks treating something that would have resolved on its own.
What causes lasting unevenness
Uneven graft survival: one side keeps more fat than the other
Fat necrosis or oil cysts: fat that died forms firm lumps
Over-resection at the donor site: too much fat removed in one area leaves a dent or ripple
Leftover fat: an area that was under-treated looks fuller than its neighbours
Skin that did not retract: loose skin over a smaller volume, common after previous weight change
Illustrative image, not a patient. A BBL result is judged once swelling has settled, usually several months after surgery.
Matching the problem to the approach
Unevenness after a BBL, by cause
Problem
Where
Usual approach
Swelling, early asymmetry
Both sites
Time and review once settled
Loose skin
Donor site (waist, back, thighs)
Non-surgical tightening; surgery if marked
Superficial excess
Either site
Surface reduction (Time Freeze Laser LCLR®)
Dent or deep ripple
Donor site
Surgical: grafting or revision
Large asymmetry
Buttocks
Surgical revision
Firm lump
Buttocks
Examination and ultrasound first
What can be done
Loose skin at the donor site after the waist or thighs have been liposuctioned is the area where non-surgical tightening has the clearest role. The VF Lift – Vertical Figure Lift and 4K Body Lift are used for laxity and superficial contour on the body. The assessment is described on loose skin after liposuction.
Superficial excess or an overfilled area can be reduced gradually from the surface with Time Freeze Laser LCLR®, which is built to target excess fat and tighten the skin at the same time.
Dents, deep ripples and large asymmetry need surgical revision: fat grafting into a dent, or liposuction of a large excess. These are referred back to the operating surgeon or to an MOH-accredited liposuction surgeon.
A firm or painful lump should be examined. Most are fat necrosis or oil cysts, but any new lump deserves assessment, and ultrasound helps show what it is.
A note on BBL safety
Gluteal fat grafting carries the risk of fat embolism when fat is injected into or under the muscle, which is why current surgical guidance places fat only above the muscle. A systematic review and meta-analysis of gluteal fat grafting reported an overall complication rate of about 7%, with seroma the most common. Any revision should be planned by a surgeon who follows this guidance.
“After a BBL I look at both ends: what happened where the fat went, and what happened where it came from. They are different problems.”
Dr Sin Yong
Frequently Asked Questions
Swelling settles over several months, and the surviving graft is usually clearer by then. Most surgeons assess the final shape only after that.
Graft survival differs between sides, and the starting shape is rarely symmetrical. Early asymmetry often changes as swelling settles; lasting asymmetry is assessed by the surgeon.
Mild to moderate laxity at the donor site can be treated with non-surgical tightening. Marked excess skin is a surgical question.
Most are fat necrosis or oil cysts, where some of the transferred fat did not survive. Any new or painful lump should be examined, and ultrasound helps identify it.
A true dent means fat is missing, so it usually needs filling, by fat grafting or another method. Energy-based treatment can soften the edges and tighten the skin around it but cannot replace lost volume.
References
Condé-Green A, Kotamarti VS, Nini KT, et al. Fat grafting for gluteal augmentation: a systematic review of the literature and meta-analysis. Plast Reconstr Surg 2016;138(3):437e–446e. source
Ahmed M, Shraim B, Al-Matwi M, et al. Comparison of complications in isolated aesthetic liposuction procedures across different techniques: a systematic review and meta-analysis. Eur J Plast Surg 2025;48:8. source
Ministry of Health Singapore. Liposuction regulatory framework. source
Schiraldi L, Sapino G, Meuli J, et al. Facial fat grafting (FFG): worth the risk? A systematic review of complications and critical appraisal. J Clin Med 2022;11(16):4708. source
This article is general medical information, not a diagnosis. It contains no prices, before-and-after images or outcome claims by design.
