Correction:His scar fades on screen when Rey heals him on the Death Star. As she heals the wound in his stomach, she also heals the wound she gave him the year before in The Force Awakens. It's an intentional detail.
Scars do fade over time (and Star Wars is a universe in which you can attach an artificial limb and leave no visible marks), but they are present throughout the film.
Correction: His scar fades on screen when Rey heals him on the Death Star. As she heals the wound in his stomach, she also heals the wound she gave him the year before in The Force Awakens. It's an intentional detail.
RazorwireRyan
He has the faded scars since the beginning of the movie.
oswal13
Scars do fade over time (and Star Wars is a universe in which you can attach an artificial limb and leave no visible marks), but they are present throughout the film.