To be frank, Scott, I doubt that what you have are herpes fever blisters, which invariably blister and scab. If you get a burning sensation with no visible change in the lip or skin, you are probably suffering not from fever blisters but from thinking too much about fever blisters. You can't transmit what you can't see. If you see something, arrange to show it to a doctor when the lesion is fresh, so he or she can diagnose it more definitively.
Best.
Dr. Rockoff