Is the light red blood that appeared on the 15th of the month considered menstruation, taking into account previous fatwas and menstrual dates, and should the opinion of Ibn Baz be acted upon, which states that there is no minimum limit for the period of purity and that menstruation can decrease and increase?

The blood seen on the fifteenth day of menstruation is considered menses. If the bleeding continues after the fifteenth day, the woman is considered to be in a state of istihada (non-menstrual bleeding). Yellowish or brownish discharge after the cessation of blood and the sight of purity is not considered menses, unless it occurs within the customary period. It is permissible to follow the fatwa of Sheikh Ibn Baz, because the common person imitates one whose religiosity and knowledge they trust.