Are the four days during which menstruation occurs slightly at night and stops during the daytime due to the use of pills to prevent bleeding considered days of menses, and what is the solution?

If blood appears fifteen days after the last menstrual period, it is considered menstruation, and prayer and fasting are not obligatory during it. Fasting must be made up, but not prayer. However, if blood appears less than fifteen days after the last period, it is considered irregular bleeding (istihada) and a vitiation that does not prevent the validity of fasting and prayer. Nevertheless, ablution is required for each prayer.