Can my indented scar be corrected, cosmetically? (photos)

Skin can certainly be improved - note I say improved and not removed !  Whenever there is a cut in the skin there will ALWAYS be a permanent scar, however the scar you have can be improved.
It looks like the underlying fat has either thinned out or was not repaired correctly and as such the skin is not adherent to the underlying structures.  This can be addressed by subcision and fat grafting to fill the defect out, however my preferred and more predictable recommendation would be to cut out the scar and repair the tissues in layers correctly.  This will lead to a much improved scar.