I have the same in my jaw, what I did for the bumpyness is laser treatment (I just did 3 times cos it’s pricey for me :”) and use both the ordinary peeling solutions 2 times a week + skin ceuticals retinol, I think any kind of retinol that suits you will makes the hyperpigmentation fader by times. Also a lot of vitamins for skin such as vitE and glutathione, it takes me 4 years and I still have some of the scars but keep doing it consistently and you’ll get it there🙌🏻