If the scar is new, massaging it frequently (using some type of serum or oil to reduce friction) can help reduce the size and how much it is raised.
If it’s more than a year post-injury, only a plastic surgeon could help.
(Info from brief training on scar management in grad school and doctor’s advice after having stitches.)
My mother once handed me the manual to a dishwasher to prove that I was loading mine “wrong.” Turns out I was doing it the way the manual recommended. She had never actually opened said manual.