Symptoms not at bite. Special treatment is not needed if a wasp sting looks like a mosquito bite but just hurts more. If the child is 2yr or older, some tylenol (acetaminophen) for pain and some oral Benadryl for the swelling & itch is ok to use. Hydrocortisone cream can also be used. If there is an "anaphylactic" reaction (rapid allergic reaction) with trouble breathing, fainting; tongue, throat, or mouth swelling; one must call 911.
Allergy consult. If the "child" is over 16 years old, even if there is generalized hives without gi, respiratory or cardiovascular symptoms, then an allergy consult for testing and consideration of venom immunotherapy would be appropriate.