After receiving a tetanus shot, if you are going to feel any side effects from it (ie- headache, nausea, etc) how long after the shot would they start?

Usually Mild: It's important to know that, in general, the risk of problems from getting tetanus is much greater than from getting a tetanus vaccine. However, sometimes the tetanus vaccine can cause mild side effects. These may include: Soreness, redness, or swelling at the site of the injection Fever Headache or body aches Fatigue http://www.webmd.com/vaccines/tetanus-vaccine#2

During the first day: The first 24 hours after the vaccine will be when you may develop symptoms. If you develop large local swelling at the site of injection, this is a sign that you had immunity to tetanus from previous vaccinations and probably did not need the vaccine. This swelling can gradually get worse over 48 hours and will slowly go down over a weeks time. It is not an allergy.