Use actives that help you get rid of it and always use sunscreen so the problem doesn't get aggravated.
Actives that help with hyperpigmentation are traxenamic acid, kojic acid, licorice root, niacinamide, retinol, Azelaic acid, alpha arbutin...
It's proven that combining at least 2 actives is most effective.
Some serums like The Ordinary's Alpha Arbutin and Ascorbic Acid or the Good molecules discolouration serum already combine two actives.
For me, among the drugstore ones, the best is ascorbic acid and Alpha arbutin. The Ordinary has a serum that combines the two. I use it every morning.
If you tolerate Niacinamide, you can use every evening the Tia'm Serum that combines niacinamide with Alpha Arbutin.
Otherwise you can use the Niod Re:pigment. It is the best but it is expensive.
Choose one and stick with it. Hyperpigmentation is a very stubborn problem and it takes times, patience and consistency.
If you use one bottle of this and then another bottle of that, it will take longer.