A mouth ulcer is a loss of part of the mucous lining of your mouth. Most single mouth ulcers are the result of minor trauma (e.g. accidentally biting yourself while eating) and will heal within a week or two. Although troublesome and painful, these ulcers are usually benign and are no cause for worry.
Some people develop ulcers in the mouth that keep coming back. Although in many cases the cause is not clear, certain underlying medical conditions can predispose a person to having recurrent ulcers.
If an ulcer fails to heal within 2-3 weeks, it is important to have it evaluated by a doctor. In some instances, these ulcers can turn out to be cancerous. If you smoke, drink alcohol or chew betel nuts, you are at a higher risk of developing mouth or tongue cancers. However, even if you do not smoke, drink alcohol or chew betel nut, it is still important to see a doctor if your ulcer fails to heal after 2-3 weeks as it may still be a cancerous ulcer.
Mouth ulcers can be caused by the following: