Cracking Jaw while cat yawning

I have a very unusual question to ask about my kitten. He's about 4 1/2 months old, and neutered. He recently had a close to death accident with his collar where he got his tooth and tongue stuck on the collar. His tongue was turning blue and the collar had to be ripped off. He was only grooming himself on his chest when it happened so suddenly.

A day later, we noticed that everytime he yawned he made a very distinct cracking noise. We thought he just kept hitting his teeth together as he closed his mouth but it didn't look like it. We thought he hurt his jaw but he's still eating and when we applied pressure near his jaw area, he didn't yelp of pain.

We are very worried as it has been over a week and he continues to make this "cracking noise" as he yawns (happens when his mouth is almost closed shut).

What could this be? He plays normally, is very active and is eating normally.

Please help!

Very worried pet owner.