Mouth lesions and sores rarely require immediate emergency medical attention, but they can be painful and embarrassing, especially if the sores are visible. A person with a mouth or tongue lesion has lumps, bumps, little ulcers, or cuts or sores inside or outside the mouth and lips. Viral and fungal infections are the main cause of mouth sores. Two of the most common causes of recurrent oral lesions are fever blisters (also known as cold sores) and canker sores. Cold sores on the mouth are likely caused by the herpessimplex virus 1, or herpes, which affects nearly two-thirds of all adults worldwide. Canker sores are small mouth ulcers that usually go away by themselves.
Any sores that persist need to be examined by your dentist.