If it is hard like bone it very well could be lumpy jaw. If it is attached to the bone and does not move like an absess, then big chances are lumpy jaw.
WE have had success if treated real early with LA 200 and an anti inflamitory as well as add iodine to the mineral.
But longer...like six months, nothing helps. The bone has already become honeycombed.
The best thing to do is ship if no fever and past the withdrawl time. We have three cases right now. They will be going to the rail grade pending vet approval.
lumpy jaw can spread. don't let them tell you other wise. If the lump breaks open, inside or out side the jaw, the bacteria will go into the water, or feed. If another animal eats or drinks close by that might have a cut in the mouth...from hay, teething etc..the bacteria enters and volia. This is why we have 3 cases right now.
We kept one that seemed to respond to treatment. Later, two heifers got it, slaughterd the first case, the hieffers got it bad, had calves at side, needed to wean the calves, the cows seemed to get better, back on hay, got worse again, now a bred heiffer got it this year. So these three animals are in quarantine untill weaning, and then they are out of here.
Lumpy jaw...bad news.
Google it and real about it.