The lips are an important element of facial beauty. It is divided into the upper lip and the lower lip, which form a horizontal slit when closed together, i.e. the cleft of the mouth. The two ends of the cleft are the corners of the mouth. There is a longitudinal groove in the middle of the upper lip, which is called the human middle (a necessary factor to constitute the beauty of the upper lip), and the crest protruding from both sides is the human middle crest. The aesthetic standards of the lips are: the midpoint of the upper and lower lip edge is located on the line from the tip of the nose to the middle of the forehead, the ratio of the thickness of the upper and lower lips is 1:1.5, the lip beads are located in the middle of the upper lip, which is the highest point of the lip arch on both sides, also known as “Cupid’s bow”, its size and shape should be harmonious and natural with the lip shape, the lip peaks on both sides are symmetrical and equal in height, and the distance from the two corners of the mouth is equal. The size and shape of the arch should be harmonious and natural with the shape of the lips, the peaks on both sides should be symmetrical and equal in height, and the distance from the two corners of the mouth should be equal in length. The curve of the lip arch should be smooth, while the curve of the lower lip edge should be gently and slightly flattened into the bottom of the boat. The structure of the lips is divided into five layers from outside to inside: ① skin: rich in hair follicles, sebaceous glands and sweat glands. ② Superficial fascia: relatively lax. (3) Muscular layer: mainly the orbicularis oris muscle. ④Submucosa: there are mucus glands and upper and lower lacrimal arteries. ⑤ Mucosa: there are mucus gland openings. I. Gridded zoning The aesthetic subunits of the lips are: upper red lip median zone (lip bead), upper red lip lateral zone, lower red lip median zone, lower red lip lateral zone, human middle zone and lip-nose lateral zone. (2) Autologous fat transplantation (a) Injection method The total amount of lip fat filling is 2-8 mL, with an average of 3 mL. Method of extraction: After local swelling anesthesia, the fat is slowly extracted with a 20mL syringe connected to a 1.5mm diameter liposuction needle under negative pressure. Fat purification: by static sedimentation method, the fat tissue was washed repeatedly with cold saline at 4°C, then centrifuged at 1000r/min for 3 min and prepared for use. The fat injection entry point was mostly chosen at the upper and lower corners of the mouth. The chin nerve and infraorbital nerve are blocked with 2% lidocaine or local infiltration anesthesia, and a 1.2mm diameter needle is inserted from the puncture point with a 1mL syringe, and after no return blood is drawn back, the needle is slowly withdrawn while injecting evenly into the upper and lower lip, and the injection level is the subcutaneous layer and the muscular layer, and gentle pressure is applied to shape after the injection. (2) Key points of lip fat injection (1) If the lips are thin and flat and lack of three-dimensionality, fat can be injected for aesthetic remodeling. Lip color is pale and aging, fat injection will not only make the lips full and soft, but also make the lip color rosy and shiny. (2) When injecting, it can be injected linearly along the edge of the red lips, and it can also be injected pointwise to the lip beads and lip red to shape a fuller lip shape, and it can also be injected at the marionette lines under the corners of the mouth. (3) Since the lip area is highly mobile and rich in blood flow, repeated punctures should be avoided to prevent bleeding and hematoma, which may affect the control of injection volume and symmetry shaping. (4) The ideal lip shape should match the shape, size and color of the nose, eyes and face in order to be harmonious. (5) Strengthen the ice pack after lip injection and avoid hot and spicy food for 3 days. (6) Avoid excessive amount of injection at one time and inform the patient that multiple injections may be required.