As someone who has taken a baseball bat to the head,
I can tell you it leaves long lasting effects some which don't manifest until later in life.
Memory loss, random blackouts and constant migrains are just some of my symptoms and I'm one of the lucky ones!.
I was pretty angry at the 3 of them for it and had it of been me in the MC's place I would not have been so forgiving!.
I would have still claimed them as slaves, but they would be spending the rest of my life making it up to me!.
Or at least as long as I remember... What what was I saying?.
I will be honest, I haven't fully forgiven Sui/Nia yet either, she needs to at least show some damned remorse about it (she was the only one who chose that option, the others were against it)!
...if we are going on the love route anyway.
On the slave route, I could see that as a possible way to but her back on the love route if the player desires.
I kind of see a confrontation (in either route) from the newly assertive Lin, who comes in to clean and sees her grumbling about her mistreatment or just about how degrading she felt the last event if it is the love route was, and Lin just goes the fuck off! "How is he supposed to treat you, after you almost killed him?!?!" or "I think you owe him a lot more than that, after what you did you him!" Then the other elves on there join in about how they asked her not to go that route with it.
This then unlocks a new scene with her where she is much more receptive, and more submissive.
For the slave route, it could be some rough sex, maybe anal, where she is apologizing until she finally gets off on the abuse.
For the love route, she comes in to apologize and service him, and that moves on to a more mutual love making session. Could have a loop on the blowjob part, where she keeps asking if he forgives her, yes moves on to the sex and no has her keep going.
Either of these could include some spanking as part of the forgiveness.