I unknowingly ran over one with the mower a couple of years ago. Got stung several times. I had tickets for a Nats game that night and went. Some swelling and itching. Got something for it he next day. As noted it hurt and itched like hell. I was stung by anothe wasp or hornet later that year and it swelled like crazy the next day and had to get something injected to bring the swelling down. So I think the first batch triggered something in my system that I am now allergic. They declined to give me an epi pen as they said it was not that bad! Needless to say I am more cautious outside now.
I think this is normal, the trigger for me was 13 fire ant stings I got during a fishing trip Texas. Since then, yellow jacket stings really make me swell up. Supposedly, their venoms are similar. Antihistamines (Benadryl) mitigate the impact.
