The probability of hyaluronic acid injection is relatively low, mainly in the following aspects: First, skin infection, redness, pain, and even pus. Second, the nose is a dangerous triangle with rich blood vessels, and nasal infection causes intracranial infection. Third, hyaluronic acid is injected into the blood, causing blood vessel blockage. Fourthly, pinhole hyperplasia and sclerosis form scars and even keloids. Fifth, the skin becomes sensitive and fragile, and it is easy to turn red when it is slightly stimulated. Sixth, it affects the sense of smell and even loses it. Seventh, because hyaluronic acid can be absorbed by the body, local skin may be skinny.