I have had a lot of bruises, too many to count, but that's really nothing. The usually thumb/toe getting caught in the gi, mawashi hitting the elbow, shin hitting a foot... nothing too special. Here are the most painful ones: Once, while blocking a mae geri, I somehow moved my hand too early and got the full force of the blow on my left thumb. It hyper extended, healed after a year. I was sparring with some skinny dude, 15 at the time, but national champion (for his age of course) so I thought it was safe to spar as usual. I did a take down and he fell on his shoulder. Didn't get dislocated, but it didn't heal until months later. The worse: I was sparring with my very best friend and he threw a fake mae geri to mawashi. At the time, I had the bad habit of blocking with my knee. Needless to say, that was pretty ugly; his mawashi hit my knee cap and a loud "CRACK" resonnated in the dojo. I had to take him to the hospital. Funny enough, my shihan was like 'oh you broke his leg' with a smirk on his face... must've reminded him of some similar accidents when he was younger! Needless to say, I felt very bad.