Depressed Bacne scars, Permanent Filler Effective?

20 years ago I had a serie of microdroplet silicone injections in my facial depressed acne scars with wonderful permanent results. Lately I have decided to have something done for my many depressed acne scars on my back which really makes it uncomfortable for me to hit the beach. Would the technique produce the same results on my back? If not, why? And can you please then suggest another technique? Thank you for your help/Anders in Sweden