Will dermarolling help flatten out or minimize the appearance of self harm scars?

Hi, I'm just wondering if I will see any results with derma rolling my scars on my left arm, they are white and sone are slightly raised. My skin is pale but the scars are still really noticeable. What length of derma roller should I get, will I even see any results? I want to at least try flatten them somehow. Any help is appreciated, thank you!