The lip is located in the lower third of the face, with the upper border at the base of the nose, the lower border up to the chin-lip groove, and the two sides adjacent to the cheeks by the labiofacial groove. The structure of the lip can be divided from outside to inside into: skin, superficial fascia, muscle layer, submucosa, and mucosa. The skin of the lip and mouth is thicker and is closely integrated with the superficial fascia and expression muscles, and contains a large number of hair follicles, sebaceous glands and sweat glands, making it easy for boils and carbuncles to occur. The superficial fascia is loose and often shows obvious edema when inflammation and trauma occur. The perioral expression muscles are divided into three layers: the superficial layer includes the orbicularis oris, the upper lip lift, the zygomaticus, the laughing muscle, and the descending corners of the mouth; the middle layer includes the corners of the mouth lift and the descending lower lip; and the deep layer includes the buccinator and the chin muscle. From the aesthetic point of view, the mouth needs to meet these criteria: The lips are appropriately proportioned, and the upper lip should be one-third thinner than the lower lip. The size of the mouth is appropriate, making a vertical line from the inner side of the black eye of both eyes, which should be the size of the corner of the mouth. The shape is curved, the upper lip shape is M-shaped, like the wings of a bird of prey, and the lower lip is a platform with smooth curves. In addition, the lips of beauty should also have obvious lip line, rounded and prominent lip beads, and deeper human middle groove. According to the width of the cleft, the lips can also be divided into three types, cherry small mouth whose cleft width is below 35 mm, is a narrow type, is a more beautiful type of female mouth; medium cleft width between 36-50 mm, most men and women’s cleft is this type; wide cleft is often greater than 50 mm, commonly known as the big mouth, the appearance is not beautiful, sometimes also need to be cosmetic surgery. Excessively large lips cannot bring beauty. Smile lipoplasty is a surgical or injection method to adjust the corners of the mouth and reorient them so that the corners of the mouth are always in a naturally upturned state. Through surgery, incisions are made on both sides of the corners of the mouth, suspension wires are buried, and then the corners of the mouth are suspended by about 3mm and then sewn on, so that the corners of the mouth are always in a naturally upturned state. Botulinum toxin is injected to inhibit the nerve endings and block the neuromuscular conduction to relax the muscles, and when the “downward muscles” that control the corners of the mouth are relaxed, the natural tendency is to uplift. The surgery is divided into two methods: internal incision and external incision, both of which require the placement of suspension wires and the suspension of the corners of the mouth by about 3mm before sewing them on, so that the corners of the mouth are always in a natural upturned state. The external incision method requires a “>” shaped incision at the junction of the red and white lips below the upper corner of the mouth to remove the right amount of skin above the corner of the mouth, mainly for sagging corners of the mouth with loose skin on the outside of the upper lip, which is more obvious than the internal incision method, but will leave a slight incision scar mark. The internal incision method is to make an incision on the mucosal surface of the corners of the mouth, and a very small incision is made on each side to remove the excess mucosa and submucosal tissues in the lips, leaving no traces in the corners of the mouth, but the lifting effect is smaller compared to the external incision method. The injection method is to inhibit the nerve endings conduction substance by injecting botulinum toxin, thus blocking the neuromuscular conduction to achieve the purpose of relaxing the muscles, and when the “shrinking muscles” controlling the corners of the mouth are relaxed, the trend of uplifting will naturally appear.