The possible causes of a painful bump behind the incisor include apical inflammation, gingivitis, and so on. 1. Root tip inflammation: the root tip suppurates and forms an abscess, resulting in the appearance of a pimple at the incisor. Root tip abscess will appear spontaneous pain, throbbing pain, biting pain and other symptoms. 2. Gingivitis: plaque exists for a long time and stimulates the gums to become inflamed and pus-filled. Localized calculus will stimulate the gums, the body’s resistance to reduce or local bacterial virulence will lead to swelling and inflammation of the gums, causing pain. Behind the incisors long meat bumps may also have other reasons, it is recommended to go to the hospital in time to improve the examination to clarify the cause of the disease, to give targeted treatment or treatment.