allergies?

I may have some sort of allergy to ... something. The last couple of days my lips have felt severely chapped, and finally this morning I took a look in the mirror and realized that my upper lip is covered in little tiny blisters. It's not at all like a cold sore/fever blister/herpes, because those are in one spot; with this, my whole lip is swollen. Thinking back, this has happened before, and my doctor gave me some steroid cream, and it eventually went away. Dr. Internet tells me that it could be a food allergy, or it could be a form of eczema. For now, I'm going to see what happens with a topical Benadryl application, and hope for the best.