(n.) The scaup duck.

birthmark bleb blemish blister bulla check cicatrix comedo crack crater craze defacement defect deformation deformity disfiguration disfigurement distortion fault flaw freckle hemangioma hickey keloid kink lentigo milium mole needle scar nevus pimple pit pock pockmark port-wine mark port-wine stain pustule rift scab scar scratch sebaceous cyst split strawberry mark sty track twist verruca vesicle wale warp wart weal welt wen whitehead