Hi help pls baby has rash!!

Hello i’m a teen mom this is my first baby, recently he’s had this really bad rash around his mouth like almost a week and there’s also rashes on his legs and arms and back. I think the body rashes are due to the detergent i’m no longer gonna use dreft and my sheets, but the mouth is concerning me the most. Also it’s on his head, sides of his ears, earlobes everything ☹️ his next appt is the 19th should I wait it out???