REACTION TO SUN AFTER BAD SUNBURN

This past summer, I got a really bad sunburn on my chest and shoulders.  The burn was so bad to where I was in alot of pain, my body was swollen everywhere I was burned- including my face.  The burn was a deep red color- almost purple, and it hardened my skin.  The morning after getting this burn, my chest had spots that looked like cigarettes had been put out on my skin.  The spots were brown and circular, and there was pus coming from them...When the burn finally started to peel, it appeared that 2-3 layers of thin skin peeled.  The skin on my chest where I got the burn does seem to be discolored since healing.  Now, since getting this sunburn, everytime the sun beats on my chest or shoulders, I get a weird red rash, only in the discolored area where I got the burn.  This rash is not bumpy, its just red and blotchy...it is slightly raised, and it causes a very slight burning feeling.  WHAT IS THIS?!