I recommend a sunscreen.

This is a product introduced by a certain male idol famous for his strict self-care. Honestly, I usually don't buy things like that because I think they're just promotions. But it just so happened that I needed to buy sunscreen, so I gave it a try. It really brightens my skin naturally, and I love it. The regular price is expensive, but they occasionally have sales. I recommend trying one when it's on sale and buying it whenever it does.