You sound as though you have or have had an infection. It may have been strep throat or tonsillitis, followed by activation of a herpes (that's why they call them "fever blisters" or "cold sores"). It may be that your body will take care of all this by itself, but I stronly urge you to see a doctor as soon as you can (walk-in clinic, urgernt care center) to find out whether you need antibiotics, are (still) contagious, or whether you have latent cold sores which may recur in the future, so at least you'll know what they are, even if you don't end up doing anything about them.
Take care.
Dr. Rockoff