Liver Flushing won't change old scars, but I can see new wounds might heal better and faster after cleansing.
For old scars, copper peptides are a miracle. It is what they use in hospital burn units. They are now being marketed as anti-wrinkle creams, though there is little proof it helps with wrinkles. I've been using Neutrogena's Visibly Firm Serum with copper peptides on a 16 year old raised scar and it is slowly and surely shrinking it.