Will your toe nail grow back after losing it?

Maybe: It depends on how you lost it and how traumatic the injury that caused you to lose it. The nail grows from an area called the matrix. If the matrix was damaged then the nail may not grow back or may grow back damaged. Having said that more often than not it will grow back, but not knowing the injury is difficult to say.

Yes: Unless the root is removed the nail will regrow.

It should: Unless there was a severe trauma which damaged the nail matrix(root) from which nail grows. Usually nail grows back. This will usually take several months depending on which toe.