Hyaluronic acid is not harmful to the body because hyaluronic acid is one of the inherent components of human skin, and its role is mainly to retain water and moisturize. However, in clinical practice, we often encounter patients who have various complications from hyaluronic acid injection, mainly due to improper operation of the injector, and the hazards are mainly two: 1, infection, in the process of hyaluronic acid injection, if the injection equipment is not perfectly disinfected or there are too many injection points, it is easy to bring bacteria or virus into the subcutaneous, and the patient may have local symptoms of redness, swelling, heat and pain; 2, vascular embolism, in the During the injection process, hyaluronic acid may be injected into the blood vessels, and if it is a small blood spot, the skin of its blood supply area may turn white and the patient will feel pain. If it is an important blood vessel, such as injecting into the ophthalmic artery, the patient may be blinded immediately. Therefore, in choosing hyaluronic acid injections, it is important to choose regular hospitals and medical institutions with skilled doctors to avoid complications as much as possible.