My 8 year old (very active healthy) daughter suddenly screams and cries because her face will begin to sting and burn. her face is not red, no marks. ?

Difficult to say: It is very difficult to say what could be causing this. Make sure she didn't put any type of chemical on it, & if that's possible be sure to wash her face with cool water. It doesn't sound like an infection or insect bite, as it would be likely be red, warm & swollen. If this goes away by itself quickly, it's likely noting to worry about. You can give tylenol (acetaminophen) or Motrin for pain.

Gastric acid reflux: May be your daughter gets acid reflux from stomach,which is causing burning sensation and make her scream. Consult your doctor, get her examined and get treated .