Rash all over body?!

I have this rash all over my body and it’s getting worse! It also covers my thighs, butt, chest, and back. I went to the ER for it a week ago and was given steroids, but it’s not helping at all.

The doctor couldn’t figure out what it is since I haven’t changed anything in my routine—-foods, detergent, soaps, etc. it just kinda... appeared one day along with dizziness and some other things. It wasn’t itchy when it started, but now it just HURTS! I can barely wear clothes cause anything touching it is painful.

Should I be worried? Is this something that just kinda happens without explanation?