The lesion that you have described sounds like a scar with post inflammatory hyperpigmentation. The treatment for post inflammatory hyperpigmentation includes various skin creams like hydroquinone, azelaic acid, corticosteroids, tretinoin cream and laser treatment.Apply hydroquinone cream on this scar and it should go away in a few days to months.If it still persists then you can go in for laser treatment, Chemical peeling or microdermabrasion. Avoid picking, harsh scrubbing, and abrasive treatments unless prescribed by a dermatologist during this period.
Also the color of moles may vary from light to dark.So no need to worry. If you notice changes in the mole's/mark’s color, height, size or shape, you should have a dermatologist evaluate it. You also should have it checked if it bleeds, oozes, itches, appear scaly, or become tender or painful.Otherwise it should be left as such.
Hope it helps. Take care and pls do keep me posted on how you are doing or if you have any additional queries.Kind regards.