I don't know when my finger started bleeding, and it didn't bleed much, but it definitely bled a little bit -- just enough to get maybe a drop's worth of dried blood under my fingernail. As I was putting Loretta back in her case, I noticed that there was a small red stain under the fourth finger on my left hand. My fingers were a little sore, but that's normal since I'm still building up my calluses. I prodded my fourth finger a little bit and noticed that it was a little more tender than my other fingers. I don't really see a source of the blood, but it seems to be a little bit under the nail. My guess is that I might have caught my nail on one of the strings and pulled it a little too hard. I certainly didn't notice it when it happened and it doesn't really hurt. I've been typing with it all day with no ill effects.
Anyway, my calluses are almost as tough as I think they're going to get, so I expect the little bit of tenderness in my fingertips to fade away over the next few weeks.
Another interesting thing I noticed this weekend happened when I picked up a guitar to play for the first time since starting my mandolin lessons. The frets on a guitar are soooooo far apart! I used to be able to make all the common chords with ease on the guitar. This weekend, it felt like I really had to stretch my hand open farther than it wanted to stretch just to make an easy "G" chord! ccohoon warned me that would happen. It was really embarrassing when I tried to play a couple of simple solo riffs -- the four frets I travel in the opening to "Day Tripper" made it seem like my hand had to stretch a mile!
I played the guitar enough to convince myself I still knew how to play and then I put it back in the case. Once I get better on my mandolin, I'll probably pull it out again and bring my guitar skills up to passable again. But I'll wait a little while, so I don't confuse my muscle memory too much while I'm learning.