It always starts with skin itchy above top lip only(sometimes it looks like a pimple), then it swells like a blister from wearing small shoes. After it swells with clear fluid it then gets bigger then smaller fluid filled blisters appear around the 1st blister. It is at first the color of my skin, then leaks the clear fluid slowly. By the 2nd day it turns red. It last about 7 to 10 days. It started about 10 years ago on my lip then would spread above lip on skin. Now it starts on skin above top lip or bottom lip only. I've never seen blisters anywhere else on my face or body. What could this be?