Bad marks are marks that reflect poorly on a person or thing. BLOTS, welts, ACNE, STAINS, stigmas, demerits, EFS, and DEES are all terms used to describe bad marks. BLOTS are splotches of ink or paint that can ruin a surface. Welts are raised, red marks on the skin caused by an injury or irritation. ACNE is a skin condition that causes pimples and blemishes. STAINS are discolorations on a surface caused by dirt or liquid. Stigmas are marks of disgrace or discredit. Demerits are marks of disapproval or censure. EFS and DEES are marks given to students for poor academic performance.