Thanks for the responses everyone. My point in posting was to see if anyone else had cut themselves similarly and knew what caused it.
Here are my responses to some of the feedback above:
RAJSH - Unfortunately, it wasn't a magazine, and if a magazine could give me a cut like this, I don't think I would handle another magazine. I agree that it had to be something metal. I originally assume the bathroom metal handle upon my pushing it open to enter, but your suggestion of the seatbelt is a possibility as well. I think a Tetanus shot shot may be overkill, but I'll let you know if I die
ADAMBRAU - I wasn't complaining or looking for compensation. I just want to figure out what cut me. I don't understand how I could have cut myself in my sleep. I just wanted to figure out what cut me and if others had anything similar happen. Sorry if my inquiry is rubish to you.
B747-437B - Because then the FA would need to log it, replace the kit, etc. for a but that wasn't bleeding badly, Vodka can clean the wound just fine and I can use paper towels to stop the bleeding. All the first aid kit would supply me with would be an alchohol swab and bandaid, so not worth opening it in my opinion.
SKYVANMAN - That's horrible. I have been hit with the carts, but a sharp edge and enough force to cut you that badly is ridiculous especially without recognition from the crew.
LaserSailor - Interesting, I never knew that. They gave me $6 (well free, since I was in BF) to clean it with Vodka.