Live in mid-fl. in yard clearing brush when bit on back of neck. after 24 hrs, swelling as big as silver dollar, still itches. am anaphylaxic?

No: If you have not other symptoms except at the bite, it is a local reaction...Benadryl (diphenhydramine) or Hydrocortisone cream.

No: You may have developed a localized allergic reaction, but not anaphylaxis which is generalized life threatening condition.

Likely not: It looks like you have local reaction to some insect bites. I don't see you mention about problems breathing, diffused rashes or hives, and abdominal pain other GI symptoms so you don't have anaphylaxis. The bite site can last for a few days. Try warm compress. If it get worse, you might have cellulitis and need to be seen by a physician.