Excess healing leads to the formation of hypertrophic scars and sometimes keloids
A hypertrophic scar
is a scar that remains very visibly inflammatory (red) for longer, is firm, raised and sometimes causes itching. It eventually subsides over time.
A keloid scar
in addition to being hypertrophic, and even sometimes even almost tumour-like, is purplish-red extending sideways sometimes in a crab’s claw shape. It persists and does not progress over time.