Canker sores are sometimes thought to be caused by HSV, but this is not true. Canker sores occur only inside the mouth, on the tongue, and on the soft palate (roof of mouth), not on skin surfaces. Although they reoccur, they are not contagious, usually are self-limiting, and have almost no complications. Canker sores are caused by substances that irritate the lining of the mouth.
Herpes sores follow a similar cyclical pattern and appear first like pimples that turn into small vesicles. Then, the skin becomes crusty, and eventually a scab is formed. It can take up to several weeks for the lesions to heal, during which time there may be one outbreak followed by another. Certain risk factors may increase the likelihood of an outbreak, such as: asthma medication, lack of sleep, stress, decreased immunity and ultraviolet rays.
The broader issue is whether, if you do get infected, herpes will ultimately harm your health. Although I don’t want to trivialize this infection, in your general scheme of health, it probably will not. The major concern is that if you are pregnant and develop a new outbreak of herpes, the virus can be transmitted to the fetus, especially during vaginal delivery. What’s more, people with genital herpes have a much greater risk of acquiring HIV if they are exposed. (It’s theorized that the lesion causes microscopic breaks in the skin, allowing HIV to enter the body.)
"When you are having an outbreak of oral herpes, symptoms usually start with a burning, itching or tingling sensation on your lips," Michael says. "This will intensify until a small rash, and then blisters, appear. These sores are commonly called 'cold sores'. The blisters are usually filled with a clear or slightly yellow liquid. Over a short time, these blisters will burst leaving a painful, raw area. These will then dry and scab over. The scabs will generally fall off after a week or two, leaving fresh clear skin beneath."