What Causes Fever And White Bump With Rash On The Face?

Hi. My 9 year old daughter has a slight fever (100 F) and complained of sore throat this morning. She is energetic and eating and drinking now, four hours later, but has a white bump with rash growing on her face suddenly in last 20 minutes. No other rash. She is not around insects and has been interacting with me at home. She has slight cough and runny nose, but nothing troublesome. I m looking on internet to see if I should be concerned about sudden bump on face. Measles is in the same state (Illinois) but she has no other rash. Thank you.