Should she, who has purified herself from menstruation and then experienced its return after a week, fast and pray?

If your menstrual period ends, then returns before the minimum period of purity (15 days) has passed, you are considered to be experiencing irregular bleeding (istihada), and you must fast and pray. However, if your period stops before its completion and then returns, it is considered a continuation of the first period. During this time, you are forbidden from fasting and praying, and you must make up for any missed fasts.