How To Cure Blister Like Red Spots On Back Of The Thigh?

I am a 34 year old female, married, 2 children. About 6 or 7 months ago I got this red spot on the back of my thigh which turned to a cluster of white blister looking things. It hurt when pressure was present (i.e. sitting down) went away after a week or 2. The the other day I started feeling the same thing again. Before it came both times it felt like my skin was raw for a day or 2, then the red mark, then the white blister looking things. Also both times it felt like my tendon was tight in that leg for a couple days. The first time it left a dark mark on my leg, and this time it came back in the same spot. I was diagnosed with genital warts 15 years ago but only had one outbreak (when diagnosed) nothing since. Any ideas on what this is? Thanks!!