If a toenail falls out, it can usually grow back. If the toenail forms damage to the nail matrix due to trauma, especially crush injuries, the toenail eventually falls out. However, as long as there is no obvious damage to the nail bed, most nails can grow back on their own. If the nail bed is damaged by trauma, or even if the nail matrix is significantly damaged, it is difficult to say whether the nail will grow out. If the nail is partially damaged, part of the nail may grow, while another part of the damaged nail or the nail bed may have difficulty growing a normal nail. Therefore, it is best to visit a hospital dermatologist to determine in person whether or not the nail bed has been injured.