Must one make up the prayers for the day on which the questioner saw purity (the white discharge) and then blood descended, or are all days considered menstruation until the fifteenth day?

The purity (Tuhr) that intersperses menstruation is considered valid purity according to some scholars. Whenever a woman sees purity, she must perform ghusl (ritual bath) and pray. If the blood returns within the possible period, she reverts to being in a state of menstruation. Purity is recognized by dryness or the white discharge (al-qassah al-bayda'). If the customary period changes by increase or decrease, all of that is considered menstruation as long as it falls within a time frame suitable for menstruation. If the duration of bleeding exceeds fifteen days, including the interspersed days of purity, then the woman is in a state of istihada (non-menstrual vaginal bleeding). She should then act as a woman with istihada, by referring to her previous habit, or by distinguishing (between blood types), or by the prevalent habit of women. She must perform ghusl whenever she sees purity. If the duration of bleeding exceeds fifteen days, she is in a state of istihada; before that, all the blood is considered menstrual blood.