Praise be to Allah.
When the new moon of Dhu’l-Hijjah appears, it becomes haraam for the one who wants to offer a sacrifice to remove anything from his hair, nails or skin, because of the report narrated by Muslim (1977) from Umm Salamah (may Allaah be pleased with her), that the Prophet (peace and blessings of Allaah be upon him) said: “When you see the new moon of Dhu’l-Hijjah, if one of you wants to offer a sacrifice, let him refrain from (cutting) his hair and nails.” According to another version: “When the ten days (of Dhu’l-Hijjah) begin, if one of you wants to offer a sacrifice, let him not touch his hair or skin with anything.”
Al-Nawawi (may Allaah have mercy on him) said: The scholars differed concerning the one who wants to offer a sacrifice when the ten days of Dhu’l-Hijjah begin. Sa’eed ibn al-Musayyib, Rabee’ah, Ahmad, Ishaaq, Dawood and some of the companions of al-Shaafa’i said that it is haraam for him to cut anything from his hair and nails until he has offered the sacrifice at the time of sacrifice. Al-Shaafa’i and his companions said that it is makrooh but not haraam… end quote from Sharh Muslim.
This ruling is general in meaning and applies to everyone who wants to offer a sacrifice, man or woman.
Shaykh Ibn Baaz (may Allaah have mercy on him) was asked: What is permissible for a woman who wants to offer a sacrifice on behalf of herself and her household, or on behalf of her parents, to do with regard to her hair once the ten days of Dhu’l-Hijjah begin?
He replied: It is permissible for her to undo her hair (if it is braided etc) and wash it, but she should not comb it. If some of her hair falls out when it is being undone or washed, that does not matter.
Fataawa al-Shaykh Ibn Baaz (18/47).
The one who wants to offer a sacrifice is not forbidden to do anything else, such as wear regular clothes, wear perfume or have intercourse.
See also the answer to question no. 70290.
And Allaah knows best.