Spider bite?

Last evening I noticed a bit of itching between my pinkie and ring finger on my left hand. Not a lot, just enough to be annoying. This morning the area was a little blistery and still itched like mad. Of course, my first thought is how in the world did I get poison ivy there? I haven't pulled weeds in a few days. I wore gloves the whole time. And honestly, that is a strange place to get p.i. from a cat too. I could see if it were on my palm or arm, but between those two fingers? As it got slightly more swollen and blistery today, I decided I must have gotten bitten by something. A spider was my first thought, followed by ants. I plan to watch it and see if it needs a trip to the doctor. I'm hoping that it will heal itself. The acid ants inject (formic, if I remember correctly) does cause blistering, and I would imagine some swelling if the bites are close enough together. Unfortunately, it hasn't been bad enough not to wash dishes or do laundry. That also means I can still knit tonight.