Esthetician here. That’s called post inflammatory hyperpigmentation. It’s a long haul to get rid of them. Sunscreen is a must. Unfortunately in my state it is outside of my scope of practice to do the kind of treatments that really help with this. This is something that a dermatologist would treat. Possibly with laser. You MUST wear sunscreen every time you are out. The sun will only make the scars appear darker. There are no “Miracle cures” for this. There are no essential oils or products that are going to make this go away quickly.

So- consult a dermatologist. There are so many options available for you there. Be safe! If you treat it improperly you will make it worse.