You have post inflammatory hyper pigmentation, it takes quiet some time to reduce.
You can use
vitamin C or any depigmenting agents, kojicare, depiwhite with good chemical exfoliation.
Patience is key in this case.
Book a direct consultation so that we can work on a good regimen for you to remove this.
Next Steps
use sunprotection, avoid any irritation
Health Tips
avoid overuse of hydroquinone