While performing Hajj is it necessary that the Niqaab of a woman does not touch her face while she is in Ihraam?Can she give some charity if she finds this difficult?
In the Name of Allah, the Most Gracious, the Most Merciful.
As-salāmu ‘alaykum wa-rahmatullāhi wa-barakātuh.
Leaving the face uncovered is part of the woman’s Ihrām. Nabi Sallallāhu Alaihi Wa Sallam has said:
“The Ihrām of a female is in her face and the Ihrām of a man is in his head.”
(Sunan Ad-Dāru Qutni, Hadīth No. 2761)
In these times of corruption and evil, it is advisable that a woman in Ihrām covers her face in such a way that the covering cloth (niqāb) does not touch the face. That is by wearing a cap and drawing the niqāb from a distance away from the face. However if we suppose the niqāb does end up touching the face, then charity equivalent to the amount of Sadaqatul Fitr is due. And if she wears niqāb whilst touching her face for a complete day, a Damm (sacrificed animal) is due. 
And Allah Ta’āla Knows Best
Checked and Approved by,
Mufti Ebrahim Desai.
Taken from idealwoman.org affiliate website-askimam.org