I had a pet tarantula for several years. I handled it frequently, and it never bit me. You probably rolled over on one while sleeping. Spiders, generally, do not prey on human beings. I have some genetic experiments that are working on that aspect, though.
Spiders are our friends.
If you can't endure them in your house, try to scoop them up in an envelope and set them free outdoors. You're right, of course, I have no evidence that it was a spider. The symptoms are similar to poison ivy, which I get a lot, except it is very localized. When I get poison ivy, it appears in more than one area, and in bigger patches. This is just a single, rough circle, about half an inch in diameter.