How long does it take for a new toenail to grow back after you've lost one?
it should start to grow back within 2 weeks. if nothing happens within a month see a doctor
As long as the nail growth zone(some mm behind the cuticle) is OK, the nail should grow back. If there's serious damage to that area, the nail may not grow back at all, come back deformed, or only partially. But even if everything is OK, it can take some months before you see it at all, and a full year for complete replacement.