I have a wart underneath my finger nail. will it go away when my nail grows over it? should i get it removed with liquid nitrogen?

Warts: Left alone, most warts will eventually go away. It takes six months to two years for the body to fight off the virus. If a wart isn't causing any problems, it may be easiest not to treat it at all. If, on the other hand, it's in a noticeable place or interferes with activity, wart removal is an option. However, I have treated warts that have been in place for 8 years.

See below: It needs to be treated. It will not go away when the nail grows over it. It will become more painful.

Depends: If you wait long enough (years?) it will go away. If you choose to treat it expect it to be difficult & painful. Consider one of the prescription creams.