Is the blood that returns a day after cessation, or the traces of blood after purification, considered menstruation, and what is the sign of the end of the menstrual period that necessitates ghusl, prayer, and fasting?

A woman recognizes the cessation of menstruation by one of two signs: dryness (the cotton comes out clean), or the white discharge (a white fluid that appears after menstruation). Once she sees the sign of purity, she must perform ghusl (ritual bath), and the rulings pertaining to pure women become applicable to her. If bleeding resumes after purity, she is considered menstruating again, as long as this occurs within the possible menstruation period (15 days), and she must perform ghusl again when it ceases.