When your skin is cut, scraped, or pierced, you will typically start to bleed, and the blood cells form a clot, which protect the wound and prohibit further blood loss. These clots can turn into scabs as they dry, and this is called hemostasis. The inflammatory stage is the next step once the wound is closed with the clot, the blood vessels can widen a bit to allow fresh nutrients and oxygen into the wound for healing.
Another form of blood cell, a white blood cell is known as a macrophage, comes to protect the wound, and these cells fight the infection and direct the repair process. Clear fluid forms to help clean up the wound, and chemical messengers, called growth factors, help mend the wound.
Next, during the proliferative phase, there is growth and rebuilding, and blood cells come to help create fresh tissue. Chemical signals tell cells to create collagen, which serves as a type of scaffolding, and additional tissues to begin the repair process. Finally, the maturation stage where strengthening occurs, and over time, the new tissue becomes stronger. Within three months, the wound is usually fully repaired.