Why can’t I take a haircut or shave after after chatos on erev shabbos and yom tov?
Answer:
It is permitted to take a haircut and shave on Erev Shabbos and Yom Tov. The prohibition applies only to Erev Pesach.
The reason for this is that Erev Pesach after chatzos is the time when the Korban Pesach is offered, and it receives some of the halachos of Yom Tov (chol ha-mo’ed).