Are mouth ulcers a type of herpes?

Generally not: Mouth ulcers are not usually caused by herpes, which is more likely to cause cold sores on the lips. However, some people develop mouth ulcers with their very first herpes outbreak.

Perhaps: Some mouth ulcers are the result of a herpes virus, while others are not. Mouth ulcers that recur in the same spot many times are often due to the herpes virus.

Possible: Possible. More likely a cold sore type of lesion. See MD for diagnosis.