Thought I had a spider bite, started as a few little red spots, turned into a blister, went to doctor, he took a sample of the liquid, came back today with no bacteria, gave me Zpack and I'm on prednisone, but now there is a rash, a little on my chest and back, on my arms, some on my legs, and it feels like a sunburn, only at the end of a sunburn when it's itchy. The spot on my arm is still sore, but just itches around it now. Now my son has a rash, doesn't necessarily look like mine, on his torso, some on his back, legs..trying to figure out if it was from one of those big blow up slides that we both went on the other day at my wife's school. I've never had this kind of rash before that feels like a sunburn. Even my face is flush.