What is the ruling on prayer and fasting concerning blood that appeared fourteen days after the end of the menstrual period, then stopped, then reappeared after three days?

If blood returns after more than thirteen days, it is a new menstrual period. The ruling for this period continues as long as it does not exceed fifteen days. If there is a period of purity interspersed within the menstruation, one must perform ghusl, pray, and fast. Then, if the blood returns, it is considered menstruation, provided that the total duration of both blood flows and the period of purity does not exceed fifteen days. If this duration is exceeded, the woman is considered to be in a state of istihadha (non-menstrual vaginal bleeding), and she must revert to her regular menstrual habit. Then, she must perform ghusl and wudu for each prayer after the end of her customary period.