Does a woman incur sin if she waits for a few days after seeing a small spot of blood, thinking it might be the beginning of her intermittent menstrual period, and what should she do in this situation?

You are not permitted to await menstruation. If you see a drop of blood and then it ceases, do not consider it menstruation, because the minimum duration of menstruation according to the majority of scholars is one day and one night. You must continue to pray and fast, and you have the rulings of pure women as long as the blood does not continue for a day and a night. You must make up the prayers you missed during the days of waiting.