I forgot to make hefsek tahara before shkeyah. I was able to get a clean bedikah on first try before three stars. I’m on birth control so my period was no very light to begin with and had ended two days before I was supposed to do the hefsek tahara. Do I need to make another hefsek tahara or can I go on counting my seven clean days?
A hefsek tahara done after Shekiyat Hachama [sunset] is invalid. Another hefsek should be done the following day and only after that may the 7 days begin [from the day after the hefsek]. If the period ended early you should be careful to note that at least 5 days have passed from the beginning of the period until the 7 clean days, that being the minimum waiting period before beginning the counting of 7 days.