Problem scars are sometimes called hypertrophic or keloid scars, this is when excessive scar tissue forms. Hypertrophic scars occur soon after the procedure, subside with time and stay within the boundary of the incision. Keloid scars develop later, usually don’t subside with time and often extend outside the side of the original incision. You might be more likely to develop a problem scar if you have a skin type known to scar easily, such as Mediterranean, Asian, African and indigenous Australian. Or if your incision has taken three weeks or more to heal, or you have a past history of problem scaring.