you're lucky you only have these on your chest and not your face, go to a derm and they will give you kenalog injections to flatten them out

Those are keloids, the ones I have on my chest and back are much bigger. But they have flattened out(some have become depressed) from steriod/5FU injections that I got from DR Fischman in NYC. They've stopped itching or being painful but the hyperpigmentation is still bad.

You need to be super careful with your ears jawline and neck area as they can keloid too. I thought I was immune to them in those areas until last year I started getting a lot of them in my jawline area from adult cystic acne. Mind you i'm 32.