Hi...the dark line you are talking about will be mostly post inflammatory hyperpigmentation...sometimes it goes even without any treatment if it is superficial but not always..so you need to consult a dermatologist who will examine and will let you know if any treatment is required. But the most important thing you need to do is start using a good sunscreen with spf 25 to 30..
Answered2016-09-22 04:31:04
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