Is there a way to brighten lips? (Photo)

Dark pigmentation on the skin can be caused by genetics, hormones,
and sun exposure. I would use a carefully curated protocol of laser
therapy, fractional ablation, Covalent peels, and topical creams. The
most important step is first starting Melarase creams for at least 6 to 8
weeks. 
AM: Melaclenz, Melapads, Melarase AMPM: Melaclenz, Melapads, Melarase PMBest, 
Dr. Karamanoukian
Realself100 Surgeon

This is not an easy task.  I would perhaps try a skin lightening cream such as hydroquinone 4% or maybe Triluma.  Also wear sunscreen to prevent further darkening.  This is most likely hereditary but also watch any products that might be irritating the lips.