Should a woman pray if she experiences a small amount of blood and discharge before her menstrual period, but menstruation does not occur, and this discharge continues after performing ghusl?

If blood appears 15 days after the previous menstruation, it can be considered menses. The majority of scholars hold that it is not considered menses unless it lasts for at least a day and a night. However, the Malikis and Sheikh al-Islam Ibn Taymiyyah do not stipulate a minimum duration for menses, and this is the more cautious opinion. Based on this, if the blood is scant and does not last for a day and a night, you are not considered menstruating according to the majority of scholars, whereas you are considered menstruating according to the Malikis. You must perform ghusl (ritual purification bath) once the bleeding stops.