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 line 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.
Hope it helps.Take care and pls do keep me posted if you have any additional queries.Kind regards.
Hey, I have a smilar problem. I was wondering if you resolved your problem? Please help with some advice, greatly appreciate it.