You could get more than a broken nose. You can lose an eye, lose teeth, or anything else. I took a hard shot to the face while sparring recently. It must have damaged a nerve because I don't have feeling in the right side of my face. I also had a black eye. It feels like I have a shot of novacane. I'm not sure this is going to go away. I hope. But that's not something I imagined happening. I also have lost toenails and my my big toenail on my left foot is completely black right when my kick landed on someone's elbow and almost got snapped off. It was excrutiatingly painful and I had to take a pain killer just to sleep that night. You WILL get hurt man, trust me. Hardly any of the guys in my class that have been training for long enough have been spared some injury, even with safety gear.
If you have a passion for the martial arts, then go ahead and do it, but don't even think of doing it just to impress girls. For me, it's more of a hobby and a great way to stay in shape as well as learning to defend yourself all wrapped into one.
