Thank you for your response. I think I will have to get to the doctor tomorrow, it's been over 24 hours, Benadryl has had no effect, and it seems to be spreading down the side of my neck. I'm wondering if this is perhaps something other than an allergic reaction?
Hives are usually allergic (food, medication, cosmetics and insect stings) but may also be due to infections, heat, cold or stress((emotional/physical). Many a times no specific cause for them is ever found.
They usually go away on their own after sometime, but in a few cases persist and medicine might be needed. The most commonly used oral treatments are antihistaminics (such as cetirizine, loratidine, benadryl available over the counter).The condition will most likely resolve after a few hours of taking these medication.
However, if the symptoms persist or increase in frequency or intensity or you experience any difficulty in breathing or sweating etc, you should immediately consult a doctor.
Do write in if you need any other information.