This why shotguns have Cast-off( cast-on for lefties) and why you don't see a lot of those "Roman Nose" comb shapes on shotguns.
Choices:
You can reduce the powder charge you are using, and thereby reduce the amount of recoil.
You can move your head back, and see if that doesn't help.
You can file down the comb and do your best to refinish- or simply strip the stock down and re-finish the entire stock. Now that you know how to do it, and what it looks like when finished, it will take you HALF the time.
Your choices are not as bleak as you think.
My Wife's Father had a beautiful Parker double barrel 12 gauge shotgun that was "dished out" on the comb to fit his hold and face. The gun went to his youngest son, who didn't want to change it. I told him that what he had was NOT done at the factory, and that while he might want to keep the butt stock as an "heirloom" to go with the gun, he should consider having a new buttstock made to fit him so he could shoot the fine gun. That son was only 2 years old when his father died, and the only memories he has are from pictures, and that gun. I didn't blame him for not wanting to alter THAT stock. However, a new buttstock made for him would cost him next to nothing compared to value of that shotgun, and would give him years of use- with the option of returning his father's stock to the gun any time he wished. The replacement stock would actually make the gun more marketable if he chose to sell it one day.( He has no children.)