But does the tetanus vaccine actually work? what does it do?

Anti-toxin antibody: The tetanus vaccine is a toxoid. An inactivated material that simulates the tetanus toxin and triggers the immune system to create blocking antibodies to tetanus toxin.If you have circulating anti-toxin antibodies, the toxin produced by a tetanus germ is neutralized and cannot give you tetanus. It has been around and found useful since 1943.

Saves your life: Tetanus is a grisly way to die that used to be very common. It's almost gone thanks entirely to immunization.