Cold sore is herpes
Cold sores are on the lips or on the face near the lips.
They are caused by recurrences of herpes virus
, which lives in the nerves after an initial infection, and then travel
down the nerves to cause the cold sores at the skin surface from time to time. Canker sores are inside the mouth, and are not from herpes, but are due to the immune system reacting to something on the inside of the mouth.