Cheek pain and inability to open the mouth may be acute wisdom teeth pericoronitis, temporomandibular joint dysfunction disease, maxillofacial gap infection and other diseases. 1. Acute wisdom teeth pericoronitis: acute wisdom teeth pericoronitis clinically will appear in the back of the face or cheek pain, accompanied by limited mouth opening. 2. Temporomandibular Joint Dysfunction Disease (TMJD): TMJD has three typical symptoms of joint popping, pain, and limited mouth opening. 3. Maxillofacial gap infection: Maxillofacial gap infection is common, such as biting muscle gap infection, which can cause cheek pain and mouth opening. Cheek pain and inability to open the mouth may also have other pathological factors, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment or treatment.