I've found a new scab on my right arm. It appears to be 3 days old and healing pretty well. Problem is, I have no idea when I injured myself. I don't recall falling or anything. It is fairly big, about 3/4 of an inch in diameter. I'm sure it must have hurt. But I've didn't noticed till today. I haven't drink or got high or anything. My only possible explanation: "I must have been abducted by aliens last week".
Now your turn... have you ever noticed a scar or a scub or some kind of injury but can't remember when/how you got hurt?