A pain in the back socket with pain in half of the face is most often seen in cariogenic pulpitis. Caries-derived pulpitis is caused by bacterial infection of the pulp tissue, which is surrounded by hard dentin in the pulp cavity, which is a contaminated environment, and once bacterial infection occurs, the pressure in the pulp cavity increases, and significant pain occurs. Moreover, the pain cannot be localized, and sometimes all the teeth on the same side and the buccal mucosa of the face, etc., will experience pain. The inability to localize the pain is also a typical clinical symptom of pulpitis. Oral painkillers in this case usually cannot relieve the pain, and timely consultation and open root canal treatment are needed to relieve the pain. Therefore, the pain in the back of the groove of the tooth and half of the face is a bacterial infection of the dental nerve, which requires root canal treatment of the tooth in order to be completely cured, and it is recommended to go to the stomatologist as soon as possible.