Most people contract the virus as children. The initial outbreak is usually the most severe, especially for children. The first episode can last or 2-3 weeks and can include sore throat and fever, in addition to blisters around the mouth.
Later episodes follow a predictable cycle. The first sign that an outbreak is coming is a tingling sensation, followed by a blister or several blisters around the mouth. The painful, fluid-filled blisters remain for several days. Finally, they crust over and start to heal. The virus goes back to its previous latent stage.
One or more triggers bring on recurrent outbreaks of cold sores. Although they are commonly called cold sores, a person does not have to have a cold to get one. Cold sores commonly appear due to stress. Other triggers include chapping or other skin damage to the lips, menstruation, exposure to intense sunlight, other illnesses, and certain medications.
Those with an active cold sore should take care not to touch it and should wash hands frequently to prevent the spread of the virus. It is possible for the virus to be spread to other parts of the body such as fingers and eyes, so not touching the eyes during a cold sore outbreak is especially important.