What causes facial stiffness after hyaluronic acid injections?

Facial stiffness after hyaluronic acid injection may be caused by the following reasons: 1. Over-injection: Excessive hyaluronic acid can restrict movement of facial muscles, leading to stiffness. 2. Physician's technique: If the injector lacks experience or inaccurately places the injection near facial nerves, it may result in stiffness. 3. Improper aftercare: Inadequate post-treatment care, such as exposing the skin to water too soon, may cause local infection and subsequent facial stiffness. To avoid such issues, it is recommended to choose a reputable medical facility and an experienced physician for the procedure, and to strictly follow post-injection care instructions.