Imagine you’re out playing some football at the park with your friends. You don’t want to hurt each other, but that doesn’t mean there isn’t some occasional contact. You run out to your position before the snap, your route already in mind.

There’s the snap. You run straight ahead, cut hard left. You look at the ball flying towards you, and so is your buddy playing defense. Right as your fingertips touch the ball, pop! You feel solid bone collide with your mouth. You fall to the ground, wondering how bad the damage is.

What do you do next?

We never like to think about a teeth or jaw injury, maybe because they’re so painful, or maybe because they’re so much more difficult to heal than a broken arm or leg. Maybe it’s because we know our teeth are permanent. Whatever the reason, mouth injuries are very common in both competitive and recreational sports, so you need to know what to do in case it happens to you or a teammate.

If a tooth is knocked out, try to find it as soon as possible. Handle it by the crown—not the root—and gently wash it off with water. If possible, reposition the tooth back into the socket. If not, keep the tooth in a small glass of milk until you get to the dentist.

For chipped teeth, you may not be able to find the part that was chipped off. If you can, be sure to bring it with you to the dentist. If not, the chip can usually be repaired in a number of ways, depending on how severe it is.

For cracked or otherwise damaged teeth, see a dentist as soon as you possibly can. Unless there is serious bleeding, do not go to an emergency room instead—without a dentist on staff, there is not much they can do for you.

And of course, always remember to wear a mouth guard when playing sports, especially contact sports like football. They’re an extremely affordable way to protect some of your most valuable assets: your teeth.