My baby girl is 8 mo and recently developed a rash that started behind her ears and on her forehead but has now spread to her stomach and back.

I haven’t done any new food or detergent. I have however switched her body wash but that was 2 weeks ago. She seems fine besides a runny nose. She hasn’t been itching or seems to be irritated by it. 3 days before the rash she was feeling bad and had a low fever and was sleeping a lot. Day 4 and she hasn’t had a fever but this rash pops up and she still seems super sleepy. Just wondering how I should manage it or what it could be ?

I added a picture but it’s hard to tell with her skin tone, it seems to be mostly flat and red with a few bumps here and there.