Is it permissible for a woman to draw her eyebrows with ink that stays on the skin for a long time to hide the defects of permanent hair loss (such as alopecia), and not for adornment?

Drawing with henna is not tattooing; rather, it is a temporary adornment that fades over time and does not alter anything of Allah Almighty's creation. Therefore, there is no harm in it, provided that it does not prevent water from reaching the skin during ablution (wudu) or ritual bath (ghusl (definition)).