Should I take him into the e.r?

My son is about to turn 2 in a couple of days. Yesterday he started to develop this ringworm type of rash. He kept complaining and scratching. I called the nurse hotline and she couldn't give me enough information on what it could be. This morning he woke up and it's looking better but now it spread all over his face. Last night he had a mild fever. Should I take him or just wait it out. ? Now the reason I'm asking if I should take him into the ER is because his medicaid is not available yet because we are having some issues with the paperwork so his regular pediatrician would not be able to see him until we get that fixed.

It's all the way down to his testies and but and waist and penis. His back is doing much better

Took him in to an urgent care and they said he has a allergic reaction but we cant figured out what caused it