My face looks dull due to skin pigmentation.

Lately, my skin pigmentation has gotten worse, making my face look dull overall. Freckles and blemishes are more noticeable than before, and because of the pigmentation, my skin doesn't look clear even when I apply makeup. I don't know if the pigmentation is caused by UV rays or by my acne scars. I've tried whitening ampoules and tone-up creams, but they don't seem to be working. Is it possible to improve my skin pigmentation with dermatological treatments? I'd also like to know how to manage it at home.