There is a type of laser treatment that actually stimulates collagen production to restore elasticity in the stretch marks themselves. It is the skin being stretched past its limit that causes stretch marks in the first place. This can happen when a person grows rapidly such as during puberty. It can also happen when a person gains weight rapidly such as during a pregnancy. The damage is actually done in the skin’s middle layer, the dermis. (The skin has three layers: the other two are the outer layer, called the epidermis, and the innermost layer, called the subcutaneous layer.)