The causes of mouth pain are as follows: First, suffered from mucosal ulcers, oral mucosal ulcers are typical symptoms of mucosal surface redness, swelling, ulceration, and ulceration surface in the encounter stimulation will cause severe pain, will affect the speech and eating, this time in the ulcers can be applied to the local watermelon cream spray or lidocaine gel, to promote the healing of the ulcers in order to alleviate the pain. Second, the lips around the herpes labialis, which is caused by the herpes simplex virus infection, will lead to blisters above the lips, and the blisters are easy to break, secondary bacterial infections and cause pain, you can apply acyclovir ointment in the herpes local antiviral treatment, if there is a secondary bacterial infection you can apply erythromycin ointment for anti-inflammatory treatment. Third, chronic lipitis, mostly due to the lack of vitamins and trace elements in the body, to eat more fresh vegetables and fruits, you can take the appropriate amount of vitamin C, vitamin B, zinc gluconate oral solution, iron supplements, etc., in order to supplement the trace elements and vitamins.