What is the ruling on the fast of one from whom blood issued after the first day of Ramadan, while she is certain that it is not menstrual blood due to her suffering from inflammation that causes bleeding?

Blood that returns is considered menstruation in two cases: if the total days of both bleeding periods and the intervening purity do not exceed 15 days (the maximum duration of menstruation), or if the period of purity between the two bleeding periods is 15 days or more (the minimum duration of purity). If the total days of both bleeding periods and the intervening purity exceed 15 days, then it is irregular bleeding (istihada), and the fast is valid and does not need to be made up. However, if it is menstruation, then the day of fasting and the prayers that were performed without purity must be made up.