After a nail separates from the nail bed for whatever reason, it will not reattach. A new nail will have to grow back in its place. Nails grow back slowly. It takes about 6 months for a fingernail and up to 18 months for a toenail to grow back.
Just so, can a broken nail grow back together?
Nails grow from the cuticle, you can wait until the nail grows long enough to cut or file away the broken part. No, but it will not look broken and won't have a high risk of breaking off completely/again. You're just glueing the nail back together, not restoring it.
What do you do when your nail gets ripped off?
Cover the nail with tape or an adhesive bandage until the nail has grown out enough to protect the finger or toe. If you trim off the detached nail, you will have less worry about the nail catching and tearing. If you leave the detached nail in place, it will eventually fall off when the new nail grows in.
Can a fingernail not grow back?
Nails grow a bit more than one-tenth of an inch per month and require three to six months to completely regrow. (Toenails grow more slowly than fingernails.) If the nail matrix is not damaged, the nail is typically capable of regrowth. The nail protects the nail bed, the skin at the upper tip of the finger or toe.