OP melasma is one of the hardest conditions to treat. I've watched Dr. Vanita Rattan on youtube who talks about treating melasma/hyperpigmentation with over the counter products. I did follow her process layering products by The Ordinary and had success with it but it didn't completely get rid of it.
Sunscreen is very important as well.
https://www.youtube.com/watch?v=9xGUYkZLwEE