I believe the female protagonist was mid-to-late teens, described in a way that, if memory serves me right, makes her of Egyptian or North African descent; desert-like setting; a prophet or god that wears a mask; and a scorpion, I believe, is involved in a way—perhaps a scorpion bite is the litmus test for divinity or some such?
So many loose ends in this description, I know. I'm only guesstimating the publication date. Also can't fully recall whether it's YA or not, but likely was YA.