First you should remember there are no any treatment that can completely remove the indented scars.Don't believe anyone who promise to completely remove it. But yes it can be made less visible with some surgical scar revision, laser skin resurfacing, chemical peels or dermal fillers.
Its hard to suggest without having a look at your scar. But if its a big one an initial scar revision surgery followed by Percutaneous Collagen Induction Therapy with Laser Skin Resurfacing might help then applications of topical silicone gel sheeting designed for scar removal may give a better result.
Again, consulting with a dermatologist or a plastic surgeon would be better option, so he/she can determine which procedure suits best for your indented scars.