M.B.
Could the rash be from the snot? I know my kids get red cheeks/rashes when they have lots of snot.
As for fever. If he has cold symptoms and that high of a fever I immediately think secondary infection that may need antibiotics. Does he have a cough? Influenza is also a possibility. DId they swab his nose and test for flu? My son had a high fever and terrible cough but lungs sounded clear at appt. He DID end up having pneumonia though, even though his lungs 'sounded' clear. The antibiotics cleared it up fairly quickly.