i have a little girl with a slight fever and rash all over her body...it started yesterday with no fever.  it looked liked it was getting better this morning, but tonight it is back with a vengeance.  the dr. saw her yesterday and wasnt concerned at all, but it looks so awful and is very itchy.
I have gone through your query, and it could be even a Chat Doctor. I would recommend you to apply calamine lotion on the affected areas twice daily and give her antihistamines likes syrup cyroheptadine for 4-5 days. This should resolve your problem.