Is it permissible for a father to differentiate between his children in treatment and affection based on skin color, and will he be held accountable for that, and is it permissible for the daughter in this case to change her skin color?

If a father taunts his son about the color of his skin, this is a grave offense because it is not permissible to taunt a Muslim about his creation, and the fundamental principle for a father is to show compassion towards his child. It is not permissible for a father to strike his son except for discipline, and justice must be observed between children in all matters so that it does not lead to them hating each other or being disobedient towards their father. It is incumbent upon the son to be patient with his father's bad behavior and to beware of offending him so as not to fall into disobedience. Changing skin color is permissible if it is to remove a defect, but if it is for the sake of beauty, then it is not permissible because it is altering Allah's creation.