Compared with materials such as hyaluronic acid and silicone, autologous fat has the advantages of convenient material extraction, no immune rejection and realistic handfeel. If not strictly disinfected, infection may occur after 5-7 days after surgery, which may manifest as local redness, swelling, heat and pain in the buttock injection area; 2. necrosis and liquefaction; 4. Nodules: the injected fat particles gather into lumps and are wrapped by fibrous tissues, and nodules may be formed by inactivation and calcification of fat cells; 5. Poor morphology: due to uneven absorption of fat, the amount of absorption is different, resulting in local depression or asymmetry of both sides of the buttocks; 6. Fat degeneration: if a large amount of fibers and necrotic tissues are mixed in when fat cells are extracted, after injection and transplantation, part of the fat will Degeneration, fibrosis and calcification; 7. Fat embolism symptoms: such as skin necrosis, which is generally rare.