1. you can tear your latex from blowing too hard. If you butt is puckering when trying to call, you're blowing way too hard. Proper calling takes very little air. (you may or may not have torn the call, it may have come torn)

2. If your diaphragm has a tear in it, and you are just learning how to use diaphragms, I'd throw it out and buy a new one.

Good luck. keep practicing... thats how to get good..