Let's assume same surgeon both breasts, same suture technique, same lack of obvious infection, and same avoidance of ultraviolet exposure. We know it's the same genetics of individual healing (and, in the same area of the body), so there can only be differences in the way the wound healed at the time of your original surgery. Both scars are flat and the left is minimally widened, but the right is definitely more discolored. Perhaps the right side had more bruising or subcutaneous bleeding (or pocket blood that gravity pooled on that right side). I also assume that one did not get more ultraviolet exposure than the other, because this can certainly cause this discrepancy.So to summarize, something (your guess may be even better than mine, since you observed the healing process) caused one side to heal and mature its scar differently from the other. BTW, these scars are completely mature and cannot be expected to change with additional passage of time.At this point, you have two options.excise and revise the "bad" scar and hope that with good technique and perfect healing you will end up with a scar that is as good or better than the present one. (Small chance it could be worse.)consider pulsed dye laser treatment if this discoloration is indeed vascular. If it is more bronze hemosiderin discoloration, or post-inflammatory hyperpigmentation, then this laser will not work. But if vascular, one treatment will lighten the capillary redness significantly, just as this laser works on port-wine stain birthmarks.I'd recommend laser treatment first, as this still leaves the option open for scar excision and revision. I hope this helps. Best wishes! Dr. Tholen