The scar could diminish in time as the skin cells die off and are replaced. It really depends on the width of the scar tissure. I had scars on my face and nose from a car accident in which glass was embedded in my tissue. A couple of scars, which were particularly deep, remain, and there is a permanent scar on my scalp, which was also from a deep laceration. The scarring on my nose is not really noticeable.
If one is in the teens or early 20's, the scar may dissipate by the time one is in one's thirties. As one ages, wounds (lacerations, particularly deep ones) produce scars that are more or less permanent. I have a nice two inch scar on my right forearm from a wound I received several years ago when I brushed my arm against the sharp tip of a nail.
Perhaps vitamin-E applied to skin might help the healing process.