In what type of dung do you specialize? Some dung has a very high acid content and could be the cause of your tongue scalloping. I know you dung beetles are resistant to any diet change, but if you would consider at least trying the droppings of another species I think you may see improvement. I have no first hand knowledge to pass on to you, but if your location is really Florida you may want to try armadillo (small piles, but I hear they’re tasty), alligator (be careful to avoid the end with teeth!), or manatee (requires getting wet).
As to the knuckle lump, the answer is silverware. Eating with your hands is fun, I know. Squishing the dung between your fingers only increases the bouquet and enjoyment, but at the expense of early knuckle joint failure. I’m afraid that’s what you’re facing, DB. Either start eating with a knife and fork (or spoon for the runnier meals) or face knuckle