My little girl bit an apple and got stung in the mouth and her upper lip and nose area is swollen. What can I do?

Take her to the doctor she could be allergic to the bee
Keep a cold ice pack on it for the time being

That will be painful, but doesn't sound threatening. I would give her a Benadryl and some buffered aspirin, 5 mg per pound of body weight. A regular 325 tablet is just right for a 65 pound dog. Break it up for a smaller dog or use baby aspirin. Do not give any of modern stuff, Tylenol, actophen, Advil, etc.

It there is very much swelling around the eye, it may be best to call the vet.