Gray nails, or onychomycosis, after the infected nails fall off, good nails grow in those with normal onychomycosis. Onychomycosis is a lesion of the nail caused by a fungal infection of the nail plate or nail bed. If the nail fungus is treated aggressively, the original grayish-white and obviously damaged nails may fall off, and if the nail matrix is not damaged, new healthy nails will usually grow back. However, if the onychomycosis is not effectively treated, the fungus infects the nail matrix, or the nail matrix is damaged by external force, the nail will not grow back after the onychomycosis is detached or removed. Therefore, the existence of onychomycosis should be early consultation, under the guidance of the doctor comprehensive standardized treatment, so as to avoid delaying the condition.