Stretch marks commonly appear after a fluctuation in weight or pregnancy, and can even appear in teenagers who have gone through a period of rapid growth. These marks can appear in a range of colors and have a different texture from the rest of your skin. Stretch marks commonly appear on the stomach, breasts, upper arms, thighs, and buttocks.
Scars form after the body has healed a wound, burn, or sore in which fibrous connective tissue has developed. They most commonly occur when the deeper layers of skin have been damaged.