Dental problems are common in bunnies. Some bunnies are sensitive to the smallest dental problem, refuse to eat esp tough food and that makes the dental problem worse, because the teeth grow all their lives and need to be worn down continuosly. Bunny molars can grow 2 centimeters per month (almost an inch), so you see how a small problem can become a big problem fast. That your bun is eating hay and grass and pellets doesn’t really point to anything being very wrong with his teeth though.

If it is the teeth, it often helps to have the molars ground/burred. That is a faily easy procedure, but the bun needs to be anesthetized for it. If the problem is with an incisor/ the incisors, the best recommendation is currently to have it removed. Bunnies don’t need their incisors for chewing, just for pulling food into their mouths, and they quickly adapt to not having incisors.

If a bunny doesn’t eat or can’t chew properly, there will be stomach problems. You get oddly shaped poop or sticky poop, the bun gets gas, and the bunny gets grumpy because it isn’t feeling well. Grumpiness and feistiness is a “good” sign in that the bunny has strenght to show anger and resentment, but the problem of course needs to be fixed before it results in malnourishment or an immune-defense weakened from stress.

Are there any other veterinaries available in your area? Even if it would mean a bit of a drive, it could well be worth it, both for a diagnosis and a cure. It’s really rather pointless to pay a lot of money to have your vets scan his head if they’re then still not able to do anything about his teeth, if there’s sth wrong with his teeth. Many people here (I’m one of them) have to take their buns for regular dentals, so dealing with bunny teeth is sth that many vets do quite routinely nowadays. But the availability of bunny-savvy vets of course depends on where you live.