I had my last tetnus shot on 10-30-2007, last night I was pulling up a chair in a casino, and when I reached underneath the chair because it had no arm rests to pull it up I felt something sharp poke or puncture my middle finger, just enough to start to see very little blood. I couldn't see under the chair to see what cut me, so I don't know if it was medal, or rust. i'm not sure if I need another tetanus shot or not?