Swollen Jaw

At the LFS where I work, I noticed today that my Niger Trigger's mouth is quite broad and swollen. I've never noticed this before and to my knowledge I haven't seen him eating. If I can get some pictures, I'll post but I only work there on a Saturday so it's hard for me to observe on a daily basis. Is this large jaw common or should I be worried?

 

Were there any long spined (diadema) urchins in it's tank. Triggers eyes are so far back on their head to protect them from being punctured while eating urchins. They can handle to toxins of the urchins but they will get occasional swelling.

 

nope only hermit crabs and turbo snails. and the occasional pieces of frozen table shrimp fed twice weekly.

 

he may have hurt himself on a hermit, my old undulated used to love carrying them across the tank and slamming them into things at high speeds

 

I'll observe his behavior and eating habits. Thanks for the info.

 

Pics update

He's been like this for at least two weeks. And not eating much at all.