The effects and side effects of hyaluronic acid are as follows: 1. Efficacy: According to the degree of crosslinking, hyaluronic acid can be divided into three categories: small molecule, medium molecule and large molecule hyaluronic acid, which have the functions of replenishing water, filling and supporting respectively. Clinically, it is widely used for lip augmentation, rhinoplasty, chin augmentation, Lisori filling, temporal enlargement, forehead enlargement, cheek depression, water injection and so on. 2, side effects: local skin redness, blood stasis, itching, swelling and other phenomena can appear in the early stage after injection, and can disappear by itself in a few days; If the doctor who injects hyaluronic acid is not qualified enough, injecting hyaluronic acid into blood vessels will lead to skin necrosis and embolism, and in severe cases, it will lead to serious complications such as blindness and hemiplegia.