Nedarim 80a: Talmud study for Daf Yomi

But rather, explain that she said: The benefit of bathing is konam for me forever if I bathe. And it is due to that reason that he may nullify her vow, as what can she do if there is no nullification? If she bathes, the benefit of bathing is thereby forbidden to her. And if she does not bathe, she will suffer temporary disfigurement [nivvula]. And Rabbi Yosei, who maintains that this is not a vow of affliction, maintains that it is possible for her not to bathe, as we are not concerned about her disfigurement.

The Gemara raises a difficulty: If so, let the mishna teach like this: Rabbi Yosei says that this condition does not involve affliction, as the content of the vow itself is irrelevant, since she can fulfill the condition.

The Gemara offers another explanation: Rather, explain that she said: The benefit of bathing is konam for me forever if I bathe today. And Rabbi Yosei maintains that nothing will happen if she refrains from bathing today, as the disfigurement resulting from not bathing for one day is not called disfigurement.