Mouth ulcers that don’t hurt and don’t heal could be cancer, or they could just be mouth ulcers. 1. Mouth ulcers are a common condition that refers to ulcerative damage to the oral mucosa that can disrupt the integrity of the oral mucosa. It may also be due to the fact that the patient has a long history of bad habits such as lip biting and cheek biting, which may cause the mouth ulcer to remain unhealed for a long period of time because the irritation is always present. 2. The etiology of oral ulcers is not completely clear for the time being, but factors related to heredity, diet, living habits and immunity may induce oral mucosal diseases. At the same time, the recurrence of oral ulcers will lead to the patients’ normal life and work being adversely affected. 3. Oral cancer can also cause oral mucous membrane ulcers, but cancerous ulcers are hard, with raised and untidy edges and uneven bases. If there are stubborn mouth ulcers, it is necessary to be vigilant. There are many other reasons why mouth ulcers are not good for a long time, it is recommended that patients go to the hospital in time, under the guidance of professional physicians, and follow the doctor’s instructions for treatment, and do not use medication on their own, so as not to delay the condition.