5 yrs after hairline lowering and hair did not grow, what could have caused this and what are my scar removal options? (photos)

Hi I had hairline lowering surgery 5 years ago, now I have a scar across my forehead. What procedure would you recommend please to hide this scar? Should I get laser to make the scar less noticeable? What kind of laser? Would laser be enough on its own or do I need a combination of laser and a hair transplant? Also the surgeon told me that I wouldn't need a hair transplant, as the hair would grow and cover the scar in about a year. What could be reason that the hair didn't grow? Thank you