Bruised nails from ball games are usually caused by the ball hitting the tip of the nail, resulting in bleeding under the nail, and blood pooling under the nail will form a bruise. If there is not much blood under the nail, you can not deal with it, cut the nail short, there is bruising under the nail will become empty, newborn nails usually in about three months will be able to completely replace the necrotic scaffolding, and when the newborn scaffolding grows out, the finger will return to the normal state. If the amount of blood under the nail is too much, the fat nail swelling and pain is unbearable, you can open a small hole under the nail cap, the blood will drain out in time, and then disinfect and bandage the fingers and nails, and wait for the newborn nails to grow out can be.