Most complications occur in the aesthetic arena and are due to over or under correction. The technique is crucial. A sharp needle can pierce an artery. Fat injected in the wrong location can block capillaries shutting off blood flow, or damage soft tissues. Other complications include infection or fat necrosis (dead fat that may potentially need to be removed through a small incision because of a "bump" felt on exam). Smoking and drinking alcohol can cause additional complications. It is important to be confident in your practitioner’s credentials and experience with regard to this special technique.