What is required of a woman who performed Umrah while veiled, having forgotten the ruling, knowing that the niqab shaded her eyes?

It is forbidden for a woman in ihram to wear the niqab. If she wears it forgetfully, there is no sin upon her, based on the Almighty’s saying: "Our Lord, do not take us to task if we forget or make a mistake." She must remove it as soon as she remembers. However, if she does not remove the niqab after remembering the ruling, the fidyah (expiatory sacrifice) becomes obligatory upon her. Even if she was unable to change it (i.e., remove it immediately), the fidyah is still obligatory, but there is no sin upon her. The fidyah consists of sacrificing a sheep, or feeding six poor persons, or fasting for three days.