What will cause the tong to go numb after having the bottom wisdom teeth removed, 2nd day still numb?

Daughter had her bottom wisdom teeth removed yesterday and her tong is numb still, what would cause this and yes her face is swollen.|||The lingual nerve that is supplying one side of her tongue was damaged from the extraction. The numbness will eventually go away but it may take weeks to months for it to get back to normal. She should make her dentist aware of the situation so that he can monitor it.