Hello,
These scars can be due to some past injuries, post inflammatory hyperpigmentation or some sort of hyperpigmentation. This darkening occurs when an excess of melanin, the brown
pigment that produces normal skin color, forms deposits in the skin.
Treatment involves hydroquinone, azelaic acid, corticosteroids, tretinoin cream and laser treatment. Please discuss these options with your dermatologist before using them.
Hope it helps.