Finger Foo

I'm one of those people who bruises if a butterfly brushes past me, so I'm pretty used to noticing odd purple spots without remembering when I bumped into something. But I'm having no luck at all figuring out what I did to the tip of my left middle finger. At first I thought I'd clipped a little too close when I was cutting my nails and gotten an infected hangnail or something -- it was swollen and warm and painful, but no radiating streaks, no oozing or pus or other serious infection symptoms, so I figured I'd just leave it alone to get better. But after a couple days it was behaving more like a burn -- sort of shiny and tender on the surface but no obvious "center" to it all. Except I think I would have noticed splashing something hot on it, and there isn't the sensitivity to temperature that you usually get with a burn, and that wouldn't explain the slight swelling of the whole fingertip. There's one little tiny red pin-spot, which made me think either a staple puncture (a hazard of pulling staples to photocopy documents -- but see above comments on infection) or maybe a bite of some kind. The problem with the bite theory is that it hasn't itched at all (which a regular spider bite always does) and the reaction isn't severe enough for it to be one of the really bad spiders. Odd, very odd.