Healing occurs by
Primary Intension - occurs in a clean cut scar, well apposed my a stich, where no pus, debris or gaping is present. Heals with less granulation and without scar.
Secondary Intention - occurs in Dirty wound, gaping with loss of tissue, wound with infection or Foreign body. Here there is more inflammatory response with more granulation tissue, scar contraction occurs and heals with scar. If severe may require intervention.