Life's Little Mysteries

I have a mysterious bruise on my finger. Yes, I said my finger. On the inside of my finger. I didn't even know you could get bruises there. But leave it to me. It spontaneously appeared last week after my first class. I was driving home and all of a sudden I felt a pain on the inside of my finger (for those of you who are wondering, it is my right-hand ring finger). It was dark in the car so I waited until I got home to look at it, and when I did, I had a bruise on the inside of the top joint of my finger. I thought it was weird, but the pain went away after about an hour or so and the bruise went away after a couple days so I didn't think too much about it. Then the other day it randomly started hurting again for a few minutes, but the bruise didn't reappear so I thought it was just a little memory pain to remind me that I still have that finger and to appreciate the fact that it is there. Well, this morning as I am getting ready the finger starts hurting again, in the same place, and the bruise is back with a vengeance. This time it is more than a bruise, it is actually swollen a bit and looking a fairly menacing shade of purple. I have absolutely no idea what I could have done to the inside of my finger to make it so mad. I don't even wear rings on a regular basis and have certainly never worn a ring on the top joint of my finger. I am getting a little worried that possibly I managed to hurt my finger's feelings a bit in some unknown way and it is now trying to get back at me. Maybe I neglected that finger in favor of the other nine, I am not sure. But I am starting to be a bit concerned that this random pain and bruising is not so random and might need to be checked out. Any doctors out there who can help me with this?