Giant wasp sting!!

Minnie • 19/England🌟
It's 4am and a fly was buzzing around my head so in my sleep I grabbed it only to realise it was a rather large wasp. It stung me on my thumb and it got me good! It's swelled up and really throbbing and I don't know what to do.
I've tried malt vinegar for about twenty minutes with no luck and have now got a clay mask on the area. I don't have any baking soda so does anyone have any suggestions? Please help I'm in agony!