A hickey is a bruise caused by someone sucking or nibbling on the skin of another person. Bruises usually appear when skin is injured by a fall, a bump, or an overzealous romantic partner. Skin discoloration occurs as a result of broken blood vessels and blood leaking into the tissues just below the skin. Women are more prone to bruising than men. During the healing phase, which may take 2 weeks or more, hickies and bruises create a rainbow of colors, including blue, purple, red, and greenish-yellow.