Question

Hello Rabbi Cable,

I was asked to find out the following. An ashkenazi woman is mistaken for a sephardi women and therefore is sent into the mikveh bein hashmashos earlier than tseis hakochovim but only realises the error several days later, what, if anything, is to be done?
Thank you,
– I

Answer

Bidieved, her tevilah was good and she is tahor. She does not need to do anything additional.