This is funny - in a coincidental kind of way. I came here to check for posts on "subungual melanoma", as well. I got out of the shower, the other day, and noticed a spot on my nailbed of my toe - not the big toe. The one next to the smallest toe. Thankfully after the inevitable google rampage, which made me late for work, I found that it looks more like a "subungual hematoma". I did get hit with a baseball in that part of my foot, and the skin bruising is gone, and I'm just hoping the toenail is part of what got hit. Can't be 100% sure without a biopsy I hate that!
Well, let us know your results/findings.