Injection of hyaluronic acid is a very exquisite technique for plastic surgeons. If the needle is pushed too fast during injection, the uniform distribution of hyaluronic acid in specific parts cannot be guaranteed. Too much one-time injection will have a certain impact on facial muscle activity, such as muscle stiffness. Therefore, injecting hyaluronic acid must go to a regular hospital. In regular hospitals, doctors are more capable of grasping the concentration and injection amount of hyaluronic acid.