My 14 month old just had Roseola about a month ago. Sounds like what you are dealing with. She started running fever out of the blue...it last 2-3 days and then almost as soon as the fever stopped, the rash came on. It was a flat rash, no bumps or raised areas. It did not seem to itch and she didn't seem uncomfortable (of course she wasn't teething though!!) If there are no other symptoms or causes for concern, I would wait and see how she does. If the rash doesn't go away or lessen in a few days, then a trip to the Pediatrician might be in order. Even if it's not Roseola, it's likely another type of viral rash and there really isn't anything they will be able to do. Of course, a raised, itchy rash could be a different story. Good Luck!