@keeprocking
I was stung on my eyelid by a wasp and couldn't open the eye for a few days but, not wanting to turn this into a version of the Four Yorkshiremen, a horsefly sting stayed for weeks, it was total agony, a massive red, swollen lump.
I've still got a scar on my leg from one I got about 4 years ago. It never got infected, it was never scratched and was liberally coated in antihistamine as soon as I realised, but it's still there, looking like a BCG scar the size of a 50p piece.
Wasps are generally easy to deal with. Don't scream, don't flap, don't throw shit at them, don't frighten them. Just move away if they're being particularly dickish and if they're just investigating, stay still or move slowly so you look like something to go around. Got taught that by a beekeeper. And obviously, if you disturb a lot of them, they're going to be pissed off and try to defend their young/Queen. Then you RUN.
When they're still working to feed the colony, they're completely oblivious to you - I had a nest about 10 yards from the back door and they all came over the garden wall, pottered around collecting caterpillars or rasping wood off the shed door and buggered off again.
Mind you, I now have to inject myself with pens that I believe are modelled precisely upon wasp anatomy in terms of thickness, speed and medication delivery rate. They sting like a bastard, no matter whether they're into my outer thigh or upper stomach (can't do the lower stomach because of stretch marks and can't do the front of the thighs because of varicose veins).