Fat can be used to fill imperfections in the skin and to create a smoother outline on the skin. It can also be used to increase the volume of the lips and to fill wrinkles on the backs of hands. The injected fat is used as collagen was used before. The fat, however, is tissue that will never be rejected by your body. Like collagen, it is likely that the treatment has to be repeated to obtain a satisfactory outcome. The only drawback to this procedure is the fat has to be drawn somewhere first. Usually this is not very problematic. This procedure is done in the office under local anesthesia. It is necessary to refine the defect to eventually get it right. There will be some swelling, and as with any procedure, there is the possibility of infection.