Whether you need an injection when your hand hits a dog's tooth cannot be generalized. It needs to be analyzed based on the specific situation:

1. There is no damage to the skin surface: no injection is needed, just wash your hands carefully with soap and water.

2. There is skin damage: If the skin is broken and bleeding, you may be infected with rabies virus, so you should go to the Centers for Disease Control and Prevention for injection in time to avoid rabies infection.

What should you pay attention to if you hit a dog's tooth with your hand and give an injection:

1. It is recommended that patients avoid smoking, alcoholism and other bad habits after vaccination to avoid affecting the vaccine. Loss of efficacy.

2. Even if you are scratched by a vaccinated dog, you should not take any chances. You should seek medical treatment promptly and let a professional doctor evaluate whether you need a rabies vaccine.

3. Get more rest and avoid overexertion and strenuous activities.