Canker Sores Are Not Cold Sores

If a canker sore appears inside your mouth, you may find it difficult to distinguish it from a cold sore.

Canker sores are not caused by the oral herpes virus, and the treatment is different.

Canker sores—tiny, shallow ulcers that cause mouth pain for about five to
0 days—usually occur on the tongue or inside the lips or cheeks.

Research suggests that canker sores develop as a response to a localized trauma or irritation.

Unlike cold sores, canker sores are not contagious and may be treated with a steroid ointment.