What are the consequences of a woman's hair and face being uncovered in front of men during Umrah out of ignorance?

As long as you are diligent in observing the hijab, there is no sin upon you if a part of your hair is uncovered unintentionally, based on the Almighty's saying: "And there is no blame upon you for that in which you have erred, but [there is blame for] what your hearts intended." As for uncovering the face in the Haram, a woman in ihram uncovers her face while in ihram and covers it if she passes by men, as 'Aisha (may Allah be pleased with her) did. So if you uncover it and then cover it in the presence of men, there is no sin upon you. If you uncover it in a situation where it is not permissible, then you must repent, and there is no expiation.