Lips seem to become less full as you age. It happened to me.
Looking back at pictures in my youth, really proves it. I used to really like my lips! Since about age 30, I've referred to them as my chicken lips. (Grateful to still have them, but they're not anything to write home about).
I tried glosses that tingle, but most just burn. I wanted something that just increased circulation.
I bought a lip pump (there's dozens on the market- pretty much the same principle). It uses suction to draw fluid into your lips. I use it before bed and when I get up in the morning.