I had pityriasis rosea in February. And this sounds just like it, it's mainly caused by stress. If you have one larger patch, then it's a 99% it's this - this big patch is called the herald patch, and usually comes first. And I know the feeling, I just wanted to completely cover up because it was horrible. You'll have to get the doctor to properly diagnose this though. You can take anti-histamines to get rid of the redness and itchyness (they usually get itchy if you get hot). It should go away in about 3 weeks, make sure you get lots of sun so the skin returns to its normal colour as when they heal the skin is lighter where the patches once were.xo
Possibly Pityriasis Rosea and should settle in a couple of weeks.Do consult your doc.