What is the ruling on women slapping their faces? And what is its expiation?

It is authentically reported from the Prophet, peace and blessings be upon him, that he forbade striking the face. This includes all forms of striking, whether for hadd (prescribed punishment), ta'zeer (discretionary punishment), or discipline. The apparent meaning of the prohibition is that it is haram (definition) (forbidden). Its expiation is through repentance and seeking forgiveness from the person who was slapped. Regarding the striking of women, it should be reviewed that it is only permissible after their nushooz (disobedience/rebellion) and when admonition and boycotting have not been effective.