How can pigmentation, which worsens with age, be managed?

These days, every time I look in the mirror, the first thing I see is hyperpigmentation, and it's bothering me. I used to have a few blemishes, but as I've gotten older, the hyperpigmentation has spread like freckles, and I can definitely feel it on my cheeks and under my eyes. It's probably because I've been exposed to a lot of UV rays this summer, and I've been working overtime a lot these past few months, so I've often neglected washing my face and skincare routine.

After losing weight and thinning my face, my pigmentation has become more noticeable, and even if I cover it with makeup, it comes back in the afternoon. It seems to be especially dark on days when I'm tired or haven't slept, so I'm wondering if my skin condition is also affecting it. I've tried whitening products at home, but I haven't noticed any significant changes.

When I searched, I found that many people said simple management of pigmentation was limited and that concurrent treatments were necessary, which made me worried. I'd like to know if treatment could improve pigmentation caused by age, lifestyle, and thinning skin, like mine. I'm also curious whether I'll notice a difference after just one or two treatments, or if I'll need to wait and see how long it will take.

If you've had similar concerns or experience with pigmentation management or procedures, I'd appreciate some practical advice. I'd also like to know what expectations I should have when approaching this issue.