The first thing to do is to contact the place you possibly had the tetnus vaccine for there will be a record of it somewhere. If you had the vaccine it is less likely that tetnus is the problem.
Have you been tested for Lyme Disease?
Hulda Clark , PhD, ND wrote that Clostridium tetnai can grow in the gut and in or under decayed teeth. This may be why you have had stiff jaw muscles in the past. I use hydrogen peroxide and modified LugolsIodine to kill these bacteria in my mouth until I can afford to have dental work done. For a buildup of Clostridia in the gut consider one of the featured programs on the Liver Flush Support Forum .