Sorry to hear about your reaction to the wasp. Since it was a wasp, and you are 100% sure it was a wasp, then it's just a matter of time until you feel better. One of my clients was bit on her ankle by a Brown Recluse spider and she didn't get any medical help until it was almost too late. She went to a jewelry show that weekend and was up and about two solid days, ignoring the pain and putting off doing anything about it. When she went to see the doctor, she was admitted and underwent emergency surgery to remove the dead tissue and begin open would treatment. That got infected and she spent almost 2 months in the hospital. It's been 2 years now and the would is almost healed back up, but there is still a hole to deal with.
I deal with wasps on jobs all the time. Once I find them, I back off and spray the area. Then avoid that area the rest of the day. The next morning, when it's still cool out, I destroy the nest. They are defenseless in cooler temps and easy to take care of. During the heat of the day, they are super aggressive and dangerous. The red, or mahogany wasp is the worse, and the one that I fear the most!!! A sting from one of them feels like somebody hit me with a hammer, and then after the impact, the burn just gets worse all day long!!!!!
Benadryl Gel helps, but just to take the edge off of it. My wife has some prescription burn cream that works great, but it's super expensive and we only have a small amount of it left. Recently I read about Preparation H cooling gel and tried it for a bee sting. That helped a lot!!!