Yesterday I was pulling virginia creeper vines down from my house and I was stung (or bitten) by something, probably sent by Skald the Rhymer. Tonight, about 26 hours after the sting, there’s a red, itchy, swollen spot about 8" in diameter. Now this probably isn’t life threatening, no anaphylaxis, but it’s annoying. I’ve put calamine/benedryl lotion on it but the swelling keeps getting bigger. I don’t need more around my middle! What can I do to make it go away?
StG
I’d go to the doctor.
When I got bit by a black widow the swelling kept getting bigger and then started moving up my arm. By day three I had red streaks running up my arm.
My doctor yelled at me for waiting three days.
He gave me some pills and I was better in a few days.
I’d not play around with it.
I’d get to the hospital ASAP. Might be a Brown Recluse bite. They’re no fun, either.
8 inches? And you’re asking if you should seek medical attention? Seriously?
Red, itchy, swollen,*** 8"*** in diameter?! Go see a doctor.
If for some reason you refuse a doctor… warm wet compresses. Actually, I mean hot, wet compresses. As hot as you can stand without burning your skin. Heat and repeat. It’ll either kill the infection (or bring it to a head to express it,) OR make it swell enough to let you know you DO need a doctor.
At the first tingle of a cold sore, hot wet washcloth, hot as you can stand, will kill the infection. A sty in your eye, wet heat will bring it to a head which you can pop and another round of heat (or two) takes the swelling down enough so it won’t come back.
When I was a child, I had an ear infection, and my mother heated a rounded river rock in water on the stove (slowly…rocks can explode,) wrapped it in a wet washcloth and had me hold it to my ear. It hurt, then hurt, then hurt, then it drained (without breaking my eardrum,) and then it was better.
When I had a pea-sized lymph node infection on my upper thigh-groin area, I took a hot shower, and by the time I got out, it was the size of an egg, cut in half lengthwise. Time to go to the doctor.
8" in diameter? I’d go to the doctor.
Stubborn? Try hot wet washcloth. 
WebMD said normal swelling can get quite big, though. I don’t think it’s an infection, just inflammation.
StG
I’d at least go to an urgent care center to have an actual medical professional look at it.
8" is a good size, and if it’s still growing, your body isn’t happy.
Mark the edges of the sting/bite as it is right now; if it gets bigger, you’ll see right away.
The medical professional will probably suggest antihistamines, and maybe steroids or anti-inflammatories, depending on what they think it is.