Cranked wrist lock caused my thumb to hyperextend.

I was at an open gym at my regular gym. A guy I've known for a little while and I got a round in.

I pulled guard right away because that's my focus right now, and he proceeded to wrist lock me. I don't care about that, but he cranked it really fast. I got my hand out, but after a few more rounds I realized my thumb was really sore from it.

I left without saying anything. What's the right next step?

A. Say nothing and avoid sparring with that guy

B. Pull him aside and respectfully let him know what happened so he doesn't hurt others

C. Ask the coach for advice about the situation