When you formally complete your Quest, there should be some form of “minor abuse reset” that forgives some of your alignment abuse, or all of it if it’s small. This basically allows you to proceed with a clean record if you only messed up one time, for example by angering a bunch of peaceful monsters.

Cavemen being illiterate makes a lot of sense, but forcing them to be illiterate is unlikely to make them fun to play when they’re already one of the least fun roles to play. So instead, the role should have mechanics that make them compatible with illiterate and a good choice if one is trying to win an illiterate game in particular. But they can also be prodded towards being illiterate by having them abuse alignment every time they read something (possibly only scrolls and books, not things like fortune cookies).

The cost of buying divine protection should increase the more you have abused your alignment.

If alignment abuse is tracked and a relevant stat separate from alignment record, the blessed scroll of punishment should give you an indication of how badly abused your alignment is, in the form of an adjective inserted into the “You feel guilty” message.