Must I repeat past prayers or fasts due to not washing my face during the ritual bath (ghusl) after menstruation, out of ignorance that it was obligatory?

If one omits the face when performing ghusl (definition) for janabah (definition), their ghusl is not valid, and they must repeat the prayers they performed with that ghusl due to their state of impurity. If they cannot ascertain the exact number of prayers, they must continue to make up for them until they are reasonably certain that their obligation has been fulfilled. It is permissible for them to follow the opinion of those who do not obligate making up prayers for the ignorant, especially if making them up entails hardship.