You can restore your morality several different ways. The cheapest way is to just buy a fake ID paper (resets your morality to 50), grindy but possible way is to help a bunch of people (people that require help, giving food to the poor, or saving imprisoned girls), or the most expensive way which is to donate a butt load of money to the church (they don't deserve your money...). But honestly, it is a huge handicap to start out as a slave so I don't recommend it. If you want to challenge yourself, more power to you. But essentially, after you escape and get the mark removed, it's just back to square one of where you started from your play through... just several days ahead with more exp... and probably a lot of wasted resources.