You can still get a tetanus shot three days after a nail in your foot. You can still get a tetanus shot three days after a nail sticks in your foot. But in principle, you should go to the hospital as soon as possible after the injury, as long as there is no disease have a role. The main component of tetanus shot is antitoxin, tetanus shot can neutralize the tetanus toxin in the blood to prevent tetanus attack, but antitoxin can only neutralize the free tetanus toxin, for the tetanus toxin has been and neuron cell binding has no effect, so after the injury tetanus shot, the sooner the time the better effect. In principle, you should go to the hospital for a tetanus injection at the first time after the injury, and it is best to have the injection within 24 hours. If it takes more than 24 hours, as long as you have not had a seizure, it is also recommended to have a tetanus injection. Tetanus is caused by tetanus bacillus through the broken skin invasion of infection, it is a kind of anaerobic bacteria, in the human body will produce toxins after reproduction and lead to a specific infection, the main manifestation of muscle tonus, muscle spasms, and may even lead to respiratory difficulties, swallowing difficulties and endanger the life of tetanus, tetanus death rate is high, so timely tetanus injection is necessary.