Some time in my early teens, I think, I noticed that I had a blue dot on my right elbow. It's barely an eighth of an inch across and looks vaguely like a faded tattoo. Honestly, I have no idea where it came from. I suppose it's possible that it's some type of birthmark, but I've never heard of a birthmark that's a small blue dot.
I took a picture of it about an hour ago. It's not a particularly helpful photo, but it's the best I can do under the circumstances. In person the blue dot is darker.
What may have happened is that I was poked or stabbed with a ballpoint pen when I was little and I simply don't remember that it happened. Maybe a little of the ink stayed in my skin and I ended up with an accidental tattoo. This scenario's not entirely that far-fetched. My sister remembers me running with a ballpoint in my mouth and tripping. The pen had no cap on it, and when I fell, the point jammed into the roof of my mouth. Then I'm told there was lots of shrieking and blood. Thankfully, I don't have any memory of this and when I look into my mouth I don't see any horrible scars or blue dots.
So, to sum up, I have a blue dot on my elbow.