Is it permissible and excusable to leave a small part of the area under the chin uncovered where the khimar is tied?

A woman must cover the area beneath her chin because it is part of the body that must be concealed. As for the chin itself, it is part of the face, regarding which there is a difference of opinion concerning its concealment. The headscarf must be tied over the chin to cover what is beneath it. The assertion that uncovering the area beneath the chin is minor and excusable has no evidence to support it, for the entire woman is awrah (private parts that must be covered), except for the face and hands, about which there is a difference of opinion.