Suggest Treatment For Rashes And Fever

my three and a half year old son woke up about a week ago with a red ring around the top of his mouth, to where a moustache would be. it was red, and if you touched it, it felt normal, not raised up or bumpy. it just looked funny. we called it his moustache and over a few days it went away. then two nights ago i noticed a weird rash on his elbows,lots of red blistery looking things, and little red spots spread out over his legs and hands and feet. but very very few of them. just the elbows looked bad. those have mostly gone away, but i looked at his feet tonight and it almost looks like blisters on his toes. mainly both sides and around the nail of his big toes. but little spots too, that arent big enough to be blisters i dont think. but its the same thing that was on his elbows. he also had a fever for two or so days about 5 days ago. not sure what any of these are, or if they even have anything to do with each other.