Mouth irritation can be caused by:
- Biting your cheek, tongue, or lip
- Wearing braces or another type of dental apparatus, or having a sharp, broken tooth
- Chewing tobacco
- Burning one's mouth from hot food or drinks
- Having gum disease (gingivitis) or other type of mouth infection
- Having hypersensitivity to certain things, such as foods or medicines
- Having certain autoimmune diseases affecting the mucosal lining of the mouth, such as lupus, Crohn's disease, or Behcet's disease
- Taking certain drugs such as chemotherapy, antibiotics, medications used for rheumatoid arthritis, or epilepsy medications
- Receiving radiation as part of cancer treatment