What is the ruling on the prayer of a 21-year-old girl whose menstrual cycle is irregular, and her period, which lasted 7 days, stopped without her seeing the white discharge, so she performed ghusl and prayed, then the mixed blood (red and yellow with viscosity) returned and is still coming intermittently?

All blood seen by a woman during a time when it is possible for it to be menses is considered menses. If the blood stops and she sees a yellowish or brownish discharge not connected to it after it has stopped, it is not considered menses. However, if the bleeding continues, along with any connected yellowish or brownish discharge, until its duration exceeds fifteen days, then it becomes clear that she is suffering from irregular bleeding (istihada).