Thank you for your question! Since most of a BBL is body contouring using liposuction technique, the complications parallel liposuction complications. I always present these potential complications to my patients which include, but not limited to: bleeding, infection, contour irregularities (unevenness), intra-abdominal penetration of organs, numbness, skin tone discolorations that could be permanent, dehydration, fat embolism and pulmonary embolism (both can be lethal). These complications are very unlikely, but it is very important for patients to know what could happen in these rare events. Because the operation can take up to 4 hours or so, blood clots in the legs could develop (known as deep venous thrombosis) that could travel into your heart and lungs. Often these complications may be magnified by lifestyle, medications, and body habitus. This is why, as surgical professionals, we advise diet and weight loss for our overweight patients. Being too overweight can increase risks of bleeding, wound healing, and blood clots. Also, reviewing the medications as some may potentially add to risks of blood clots such as hormone replacement therapy and birth control pills. The fat transfer portion of the operation has its own unique set of complications. Inadvertent intra-venous injection of fat could prove the most serious complication as the fat could travel to the heart and lungs. Fat necrosis from transferred fat not being cleared by your system and can coalesce into fat cysts and hardness in the buttock. This may require aspiration at a distant time after the surgery. To note, pre-operative dimples in the buttock most often are not corrected by BBLs and can be interpreted as a side effect to surgery. Rather, the dimples could possibly be exaggerated with BBLs. Please discuss this with your surgeon. Other side effects, I have seen more commonly include skin discoloration especially on the side of the abdomen and inner thighs. This may be due to hemosiderin staining where the iron in red blood cells can "stain" a region and may take months to clear, less commonly permanent staining. I hope this helps those interested in BBLs.