Is it permissible for the woman in Ihraam to cover her face?
It is permissible for the woman who is in a state of Ihraam to cover her face with an adjoining/alternative (cloth) other than the niqaab and the burqa’.
Shaykh ul-Islaam Ibn Taymiyyah
Ikhtiyaaraat al-Fiqhiyyah min Fataawaa Shaikh ul Islaam Ibn Taymiyyah page 117