Recently, any time I get hot my chest, back, face, arms, and even parts of my feet flush red and I get an intense stinging sensation everywhere. My chest and back get especially red. It looka as though I have a blotchy rash all over. It goes away if I stand in front of a fan for a few minutes or take a cold shower. My skin also gets hot to the touch. It hurts so bad; it feels like I am being pricked by a thousand needles. Any idea what this is and how I can get it to stop?