I would like to know this. i've scoured the boards and google and i've yet to find a conclusive answer.. most say that PIH is temporary and the skin will return to its original colour, but i have brown marks on my face that are almost 4 years old. 4 years ago i also scraped my shins and got a chemical burn trying to treat them afterwards. the results of that were scabs that fell off and turned into brown marks which are still visible on my legs today. i don't get it. does dermal hyperpigmentation go away too if you manage to penetrate the skin and stimulate it, with skin needling or lasers, for example? i would really like some answers!
No one could really answer this question for me either. I've had mine for 6+ years and I know they're not going anywhere on there own. If you're just waiting for them to fade, I'd say from personal experience, don't hold your breath. I'm currently waiting on a TCA peel which is 'allegedly' a surefire weapon against PIH. Look into it if you're interested.