And there is no place for reacting with shock in the mikvah. The mikvah lady is there to help another woman perform her mitzvah properly. She is not there to look askance at ANYTHING, and certainly not to judge. If there is a problem of some kind, she needs to discreetly call a rov to ask a shailah.
If she trains herself (as would a doctor examining a patient, or a therapist hearing a patients’ recitations of what bothers them) to refrain from reacting one way or another, it would not happen. These women who are now frum, but once possibly were not, ALREADY are self-conscious about their bodies. It is some form of onaa to make them feel worse about themselves by betraying one’s personal shock with an obvious look.
I know that I am expressing myself strongly, but that is because this is a particular soap box cause with me. So many women have diffculty performing this crucial mitzvah, whwether physically or emotionally. Should we add to their discomfort? How many women have been turned off because a mikvah lady looked at them the wrong way when they came in wearing pants, or sleeveless shirts? They are still women coming to do a mitzvah, and we want them to WANT to be there.