I completely understand your concern and I hope I am able to help you for the same.
Since you have melasma
, I would advice that you use some kind of a lightening agent like kojic acid and vitamin c combination over the scar.
This is a simple, harmless lightening agent which can be used for as long the blackish pigmentation is there.
Use proper sunscreen (spf>26) before going out in the sun so that the lesions doesn't darken any further.
Take a diet rich in vitamin C and antioxidants like Citrus fruits and lots of salads
Hope it helps
Best wishes for a speedy recovery
Dr Geetika Paul