Cold sore support groups

Cold sore

Various types of sores can appear anywhere within the mouth, including the inner cheeks, gums, tongue, lips, or palate. Cold sores are caused by herpes simplex virus and are very contagious. Usually, you have tenderness, tingling, or burning before the actual sore appears. Herpes sores begin as blisters and then crust over.

Sources
MedlinePlus - Mouth Sores