This clot forms a shield to protect the cut surface so that cells can migrate to the wound to repair it. The clot contains platelets mixed with fibers and plasma, as well as growth substances that get the healing process started. There is an underlying contractile connective tissue that shrinks to bring the edges of wounds toward each other. It does this because chemical signals are sent out by the wounded cells to be received by nearby tissues to start the repair process. In skin there is a system of sensory nerves that are exquisitely sensitive to signals released afer an injury.
New nerves sprout at the wounded site that seem to be controlled by a nerve growth factor.
Scientists are searching for all of the specific chemicals that foster healing and which ones can signal other cells. If we knew more we could apply treatments that heal wounds without producing scars and with full regeneration of hairs and glands. Also we could hasten the speed of recovery especially with skin burns or for accidents that cause extensive skin damage.