1. What are Stretch Marks? Strech marks are scars left behind when skin is overstretched, and fibers in the middle layer (dermis) have broken. They most often occur during pregnancy, bodybuilding, extreme weight gain, occasionally puberty and are usually found on the abdomen, breasts, buttocks, legs, and upper arms. Fresh stretch marks appear initially as red lines and then slowly fade to a pale white color over the course of…