Okay so the extend of my fever blister experiences have been just my lip swelling up a little bit, then it going away. Now i've got this big ulcer like thing on my upper lip, inside and out and am using this perscription cream to try to get rid of it. I just need to make sure that I don't need to go to the doctor and get special stuff to treat it, im 14 weeks along. I would've figured not but just in case I thought i'd ask.