Yellow jacket sting help?

I have been stung by yellow jackets and wasps before (I am in Southeast US) and have not had any allergy probs, but my mother was alergic enough to need an epi pen to prevent shock. I have not been stung in over ten years until yesterday. About 24 hrs ago I got stung by 3 yellow jackets and apparently am ok, except that one stung me in my forearm and it is still very swollen and painful. It stung me on about 3/4 of the way between wrist and elbow on the top or distal side of my arm. Now, my whole area between the sting site and my elbow is very swollen all the way around and it is achy in my elbow joint. I am sure the pain is from the swelling but is this serious? It seems to have a good bit of heat in it. Should I go to a doctor? I have not treated it at all and am going to take some Benadryl I think. I did not take any Benadryl yesterday because a friend had died and we were drinking at his wake and I didn't know if it would be good to be drinking on Benadryl- question again- I do not feel drowsy taking Benadryl, but is it safe to drink on it? Is this sting going to get worse-it has been 24+hrs? I should be ok, right.