Usually I don't see the rash cause I'm wearin pants but I always get super itchy there on my legs to the point that I have to get off the treadmill. Today after 10 mins on the treadmill out of nowhere I started itching so much that I had to get off. When I got off, I seen this on both of my legs at the same spot. Itchy and warm to the touch. I got scared so I went home. The rash is still kind of there now. (This happened like 20 mins ago)

What is this? Does this happen to anyone else, or should I be worried? I don't sweat on my legs... Just my back sweats...