A chunk of skin can reattach as long as the wound is not too deep and your skin's stem cells also remain intact.
Your skin regenerates from the edges inward and from the bottom up.
Although the regrown area of skin will likely also form scar tissue and may even lack sweat glands or hair.
For partial thickness wounds, if the injury that removed the skin only removed the outer layers of the skin or epidermis and part of the inner layer also known as the dermis, then the skin can regenerate completely with little to no visible scarring.
For full thickness wounds, if the entire chunk of skin was removed, revealing underlying muscle or fat, the body will prioritize sealing the wound over any perfect skin regeneration.
And it will fill the gap with connective tissue or collagen, which results in a scar.
And if the damage to the skin, destroys the structures that are responsible for hair growth, pigmentation and oil production, the new skin might permanently lack the glands and follicles.
To maximize and promote healing of skin that was removed during an injury.
Keep the area clean and moist.
Gently clean the area with some mild soap and water and apply some petroleum jelly and cover it with a bandage.
Doing this creates the ideal environment for cells to migrate and prevents the scabbing from drying out.
And avoid antiseptics as harsh chemicals like hydrogen peroxide or even rubbing alcohol can actually damage the new and delicate skin cells and actually down the healing process.
If the wound is gaping or won't stop bleeding after 10 to 15 minutes of applying pressure you should see a doctor.
Or if the wound is severe and need stitches you should go to the ER for treatment.