Fever blister i've had them all my life and generally treat with valacyclovir. this one has been unusually hard to heal and has seemed to start over from the beginning when it was almost gone, and has seemed to start spreading away from my lip. i've also

Cold : Cold sores or fever blisters are caused by herpes simplex virus type 1 (hsv-1) and are extremely common. Most people become infected as an infant or small child when kissed or by sharing eating utensils with an adult who has the virus. The virus is most contagious when someone has a cold sore, but can still be passed along by someone who does not. Many people do not even know that they are infected because the virus can "hide out" in the nerve cells for very long periods of time - for some people it hides out forever and they never get a cold sore. For others, the virus can "wake up" and that's when a cold sore happens. No one knows exactly what causes a cold sore to appear - sometimes stress, illness, fevers, colds, sunlight, cold weather, menstruation, certain foods, allergies, you name it! they usually last 7-10 days and are more of an annoyance than a danger unless you have a weakened immune system or contract a bacterial infection on top of the cold sore (impetigo). If your cold sores do not resolve as usual in 7-10 days or seem to be worsening, you should see your doctor. You could be developing impetigo again or if you have another skin disease such as eczema, you may need more aggressive treatment to get your cold sores under control. Good luck!

Typically : Typically cold sores last a week or two so this may be impetigo or another diagnosis. I would recommend you see a dermatologist who can perform a culture of the area if the diagnosis is in doubt. Another option you can consider is using valacyclovir on a daily basis to prevent cold sores. I hope that helps.