Rash after fever?

My 1 yr old had a fever on Thursday night, then on Friday, then Saturday his fever broke. He did have loss of appetite, and has been tired. Very cranky. Doctor said it could just be a virus but she didn’t specify she just told me to do Tylenol for his fever and to hydrate him. Well today (Saturday ) he didn’t have a fever all day and tonight around 8:30pm I noticed he has this rash. Does anyone more what this is? His dr is closed until Monday. It’s only on his stomach, one side of neck and some of his lower back. No cough, or anything like that. Fever never rose above 102

When I look online I see things like roseola or HFMD and that worries me cause it says it’s a herpes virus does anyone know if it can just be a regular rash or does it have to be one of those bad rashes?? Ima FTM so this stuff worries me. I don’t think it’s heat rash since he hasn’t been hot or anything