The scar is a waste product along with Calcium expelled from a wound as a "dumping" grounds and scab to seal the wound.
"IF" your health was perfect, you had really clean balanced blood, then the calcium would have dissolved as fast as it appeared and you would never know you had been wounded.
"IF" the scar is from an operation, they are the hardest to remove, for the simple fact that numbing fluides were used or in addition pain drugs were used, making the blood too ill to complete the healing as Nature intended.
The calcium / magnesium balance was not perfect and few people do have such perfect blood, so scars are common.
"IF" your wound is fresh, I find that cayenne pepper or a formula of cayenne pepper placed in the wound and kept there a few days, usually leave no scar.