Should I still get a tetanus shot, if my skin was barely punctured from a rusted metal jagged edge?

Tetanus booster. It depends on when your last tetanus booster was and how tetanus prone your wound is. Your primary care doctor should be able to give you more fine tuned guidance on whether or not you should get a booster.
Depends. If you don't remember your last booster, never had the shot, or had it more than 10 years ago you need to. If it is close to 10 years you might just get one so you will hive yourself covered for another 10 yr. Tetanus spores are around us in nature like any germs. Any break in the skin can allow them in.