Dynamic lines, also known as expression lines, are wrinkles that appear when facial muscles make expressions, such as smiling. Hyaluronic acid injection of dynamic lines is the method of injection, small molecule hyaluronic acid material into the facial dermis, to enhance the water content of the facial skin, increase cellular vitality, to achieve the elimination of facial dynamic lines, to promote the effect of facial skin rejuvenation. However, if you choose irregular medical institutions or do not pay attention to the operation specification, it may produce the following risks: 1, rejection reaction: manifested as a transient allergic reaction, mainly from the residual bacteria or animal protein in the production process, or decomposition products activate the immune response, resulting in different degrees of rejection reaction; 2, localized redness: localized redness is a common phenomenon, physiological redness will disappear within 1-2 days If the redness does not disappear after 3 days, we should go to the hospital for follow-up and timely treatment; 3, subcutaneous bruising: If the needle touches the tiny capillaries during injection, there will be subcutaneous bruising, that is, bruising, usually bruising will slowly disappear in 1-2 weeks; 4, local swelling: swelling may occur after injection, 1-2 days will slowly disappear, if it lasts longer, we need to seek medical treatment; 5, infection: This situation generally does not occur, but if the operator’s sense of asepsis is lacking, it is very likely that the bacteria will be brought into the surgical bit area, infection may occur; 6, embolism: hyaluronic acid injected into the blood vessels, embolism may occur, serious embolism can be embolized respiratory and circulatory system, endangering the life.