You need to do more than ice and pain killers for a sting. What sort of wasp was it? Did it leave a stinger behind? If so, it needs to be removed.
Vinegar or lemon juice can neutralized the venom. Wet tobacco can help or make a baking soda paste. Some people advise mixing the baking soda with vinegar and applying that.
It takes about 20 minutes for the vinegar to make it stop totally.
If you have that much pain from one sting, there is a distinct possiblility that you have developed an allergy to the venom, and may need to have an epi pen or something to take in case of future stings.
JMHO.
I would not have been capable of making baking soda paste or wetting tobacco. I had nausea from the intense pain. If I had started having symptoms of anaphylactic shock, would have dialed 911 as I was not capable of driving.
I just think the wasp (and I didn't see it clearly as I was stunned by screaming pain and trying to fast figure out what happened), was able to unload all the venom it had into that finger. Really, it was so bad all I could think of was instant ice and don't faint. The nausea hit just before I got the ice on it and that feeling stayed until the pain level came down a bit. The thing is, I have a high level of pain endurance and this stripped that completely away and I was jelly.
I don't think the stinger is in there and if it is, it can't be seen. I really hope it will be much better in the morning. I hate this happened for I will never open a car door again until I look behind the handle.