There are different types of lasers that are useful for skin rejuvenation. Fractionated laser can be ablative, meaning that it removes the superficial layer of skin and works by the body creating a new superficial skin layer or non-ablative which is a less deep laser treatment. The deeper treatments are better for wrinkles, the less deep treatments are better for skin texture. Both stimulate collagen because they create tissue injury. Once you create tissue injury, collagen is stimulated. However, collagen stimulation and skin thickening are not the same thing because if a lot of tissue is injured the skin might actually not produce enough collagen to overcome the injury so both answers are correct. You really need to see a specialist to determine what treatments are necessary, if any, to correct the condition. If it is a pigment related issue, light-based treatments such as IPL are often preferred over Fraxel. If it is a skin-thinning issue, treatments such as Sculptra can be excellent to produce collagen and help with shaping the face and improving fine lines. Seek out an injection specialist, aesthetic surgeon or a board-certified dermatologist who can advise you as to what procedure will work best for you.