The back is not like the face, no vascularity, slow healing. The best you can do here is CO2 laser and steroid drip. Vitamin E you can try if you wish, or a bleaching cream if you have PIH. Look at the skin section of the FAQ PIE/PIH.

Thank you- have you tried the c02 laser?

and how much change can from it?

You won't get 100%, but a percentage of healing that is all personal to your healing capabilities and how you respond to treatment, This is one area of treatment that is not the best evolved to helping fully. The body does not heal as well as the face, not as vascular and thick touch skin. There have been some great co2 steroid drip jobs and then us vascular laser on them for color. The best you can do in this case is flatten them and get the color to blend in well with the body.

Hypertophic scarring on the body is a real problem.