Must the questioner make up the prayers she missed due to her ignorance of the rulings on purity, and how should they be made up if they are obligatory?

Yellowish and brownish discharges are considered menstruation if they occur within the usual period, and prayer must be abandoned at that time. However, if they appear after the usual period, they are not considered menstruation, and prayer should not be abandoned. If you abandoned prayer in this case, you must make up for it because it is a debt upon you, and making up the debt of Allah is more deserving. If you are unable to determine the number of prayers, then act with careful investigation and make up what you most likely believe will clear your conscience. Sheikh al-Islam Ibn Taymiyyah holds that making up prayers is not obligatory in this case if the abandonment was due to ignorance or misinterpretation. The first opinion (of making up the prayers) is more cautious and more absolving of responsibility.