Dark spots aren't real scars. Scars can be atrophic or hyperatrophic
if there is inflammaton or irritation of the skin or even sun burn, hyperpigmentation can be formed, especially in people of color. The damage caused to skin would make the melanocyte produce more melanin to protect and heal the skin Thus, you have hyperpigmentation.
To CORRECT hyperpigmentation:
1) You can make use of exfoliants such as: alpha-hydroxy acids (AHA): glycolic acid, lactic acid, malic acid, or mandelic acid.
2) Or, you can exfoliate using beta hydroxy acid (salicylic acid) or beta-lipohydroxy acid (capryloyl salicylic acid).
NOTE: Glycolic acid has been researched the most. Products with AHA in 5-20% concentration have been proven to be effective and safe at pH 3-4. while, products with BHA or LHA have been proven to be effectuve and safe in 0.5-2% concentration at pH 3-4. The amount you apply should be based on your skin ability to withstand the acid. You can make use of higher concentration as your skin get used to it
3) You can make use of skin lighteners like: Hydroquinone and its derivative (arbutin), kojic acid, vitamin C (L-ascorbic acid) and its derivatives (e.g., magnesium ascorbyl phosphate, sodium ascorbyl phosphate, tetrahexyldecyl ascorbate and a few others), vitamin B3 (Niacinamide) and its derivative (Myristyl Nicotinate)
NOTE: Hydroquinone is the GOLD-STANDARD. Over-the-counter strength is 1-2%.
To PROTECT and PREVENT future darkening:
1) You should use a sunscreen of spf15 or greater. You should reapply after swimming or persipration.
2) avoid going in the sun from 2-4 pm because the sun is intesified at this time
It can take 1-2 months to see result depending on how you use the treatment,and you can meet with your doctor for a prescription of hydroquinone in 4% or tretinoin
hope i helped
People who like home remedies can simply apply aloe vera on face for half an hour or can leave it overnight on face. Wash it with mildly warm water & apply moisturizer. It is old but still effective way to lighten the darken spots.