Thank you for your question.
A hefsek must be done before sunset. It doesn't matter when the cloth was taken out, as long as it was inserted before sunset. (If you missed sunset by just a few minutes, it's worth noting the time and asking a local rabbi whether you can count it.)
You should do a new hefsek tomorrow, and start counting the seven clean days the day after that. Make sure your hefsek is completed before sunset. In general, if you know you are busy and might forget, I suggest you do a hefsek earlier in the day and then repeat iit at the preferable time in the late afternoon. Should you forget, the morning one is valid (in the rare case of only one day of bleeding please contact us how to proceed).
It is best to repeat the hefsek as we have outlined. However, should you forget, the late one done this evening could be counted for the next day (e.g., if you did a hefsek Monday after sunset, it could be counted for Tuesday, and you would begin your seven clean days on Wednesday). However, to prevent confusion with this important mitzvah, please get back to us if this actually happens.
This internet service does not preclude, override or replace the psak of any rabbinical authority. It is the responsibility of the questioner to inform us of any previous consultation or ruling. As even slight variation in circumstances may have Halachic consequences, views expressed concerning one case may not be applied to other, seemingly similar cases.
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