The high safety of hyaluronic acid makes it very safe to inject hyaluronic acid into the cheek, and human skin tissue will not produce any rejection, generally speaking, there is no side effect. Moreover, the effect of injecting hyaluronic acid on cheeks can last for about one and a half to two years. If the effect is not satisfactory, it can be re-injected after hyaluronic acid is completely decomposed and metabolized.