I practice TKD, and 17 days ago, doing a roundhouse kick to my sparing opponents ribs, I managed to rip my big toe nail out of the cuticle of my right big toe. Bled like mad, and I also popped two holes in the ball of my big toe, which also bled. After 17 days, the toe is still quite sore on the bottom. My guess is that the bone in there is bruised. Its healing, slowly. My solution is to buy and wear appropriate shoes and not kick or practice barefooted. My leg strength for kicking is quite strong, but as was noted by someone here already, the tops of the feet are not for kicking. So wear shoes. They're cheap and effective protection for you. My left big toe is also black from bleeding under the nail. Its the impact of the kicks, which our nails are not meant to deal with. The guy commenting on the superiority of the shin strike is correct, and fighting for points as in WTF point fighting is a bad idea. Forget points and go for wins in actual fighting. Shin strikes are far superior.