I’d start with topicals, a good absor of acid and tretinoin, the latter heavily buffered at first. Go to the reddit tretinoin sub to learn more. A TCA peel could work too. I’m less familiar with lasers for hyperpigmentation, but there are some.
Whatever you do, wear a really protective sunscreen or the hyperpigmentation will recur. The L’Oreal Anthelios ones are expensive and can be heavy, but they protect much better hr a mist American sunscreens.