Is it effective for treating melasma, even on faint pigmentation spread across the cheeks?

Lately, when I look around my cheeks, I am concerned about the faint, widely spread brownish tint rather than distinct, dot-like pigmentation, so I am looking into melasma treatment.

It’s not just one or two dark spots; the inside of my cheeks and near my cheekbones look generally dull, so I’m not sure if it’s just blemishes or melasma.

On days when my skin is dry or tired, the color seems to stand out more.

Can I expect effective melasma treatment even in this case?

I am wondering if melasma treatment is only necessary for people with dark pigmentation, or if it is sometimes started even at the stage where it is lightly spread out like mine.

I would also like to know if it is necessary to first confirm whether it is actually melasma or another type of pigmentation before receiving treatment. Rather than suddenly brightening my skin tone, I would like the patchy appearance to be naturally evened out.