delete the keys folder in the cheathappens folder in your documents folder OR from the trainer instructions itself:
"To delete your Custom Hotkeys for
this trainer, press the Debug Tab and then press CTRL-K and the keys
will be deleted."
I interpreted their question as: "Can I reset my stats back to 'normal' after messing around with the FKey options?" So in case that's the case...
Short answer: No.
Long answer: You can change the mod value of the stat options in the trainer by clicking on the trainer option. It accepts both positive and negative values. If you know what your stats were before you started "playing around" then you can just modify the option(s) to remove the excess points from each stat.
For the record I do not know if redistributing your stats at Rosaria would make them right. I imagine it would, since you're re-doing the level up process. But I'm not 100%.