My 9yo has had a head cold for a couple days. Been taking children's cold/cough medicine for stuffy head, etc. Last night he got into the bathtub and his legs and arms are all red, not raised just a red flush on those parts and some on his stomach. He slept good last night but the rash is still there today and it's warm to the touch. Is this just from the medicine or the cold virus? Not sure if we need to take him to clinic as it doesn't itch or anything. Thank you.