Q: Is a woman obligated to shower after immersion in a Mikveh?
A: No, just the opposite. Our Sages decreed that a woman should not bathe after immersion in the Mikveh. Women used to bathe after immersing in a Mikveh since they did not immerse in clean mikvaot as we have today. They immersed in pits of water which were filled with mud and they emerged filthy, so they bathed afterwards. As a result, people began to believe that both the Mikveh and the bathing were required for purification. The Rabbis therefore decreed that it is forbidden to bathe after immersing in the Mikveh (Shabbat 14a and Rama to Shulchan Aruch, Yoreh Deah 201:75). We have similar problems in our time. Although our mikvaot are extremely clean, there are women who are sensitive and feel that they need to bathe after the Mikveh. Even though a man's immersion in the Mikveh is less strict than a woman's immersion (since in the majority of cases he is not obligated to immerse), there is a story in the name of Ha-Rav Shlomo Zalman Auerbach that he would bathe before and after immersion in the Mikveh. The students asked why he acted this way. Ha-Rav Shlomo Zalman said: I shower beforehand to fulfill "Love your fellow as yourself" - so I do not make the Mikveh dirty and I shower afterwards because of those who do not fulfill "Love your fellow as yourself" (Ve-Aleihu Lo Yibol vol. 2, p. 286). Regarding women who want to bathe after the Mikveh, it is permissible to wash the body one part at a time: the hands, then the feet, then the head, then the back, et Ha-Rav Yosef Shalom Elyashiv created a "Chidush" (innovative ruling) that a shower does not wash the entire body all at one time but part by part. And even if the shower covers the entire body, each drop of water is still separate and touches a different part of the body. This "Chidush" allows women to shower after immersion in the Mikveh if she wishes, but she is certainly not obligated to do so.