What's the piece of grissle called between the nostrils?

septum?

Yep. It’s called your septum. I also believe that there is a nerve there.

I love the word gristle.

And when you get hit in the nose with a softball when you are fourteen, and your nose looks like this / instead of this I, it is called a deviated septum.

I love it! / or I. Deviated gristle!

Thankyouverymuch.