^^I wouldn't use a skin bleaching cream on my face let alone my lips! ITA i don't think they are safe for lips.
I found that if I use concealer on my lips, it changes the color of the lipstick. I don't like that. Although, I have not tried using my foundation (never thought of it either) which is water resistant and has little transfer. i might try that. I have a dark upper lip and a light lower lip (which I think I have sexy lips ). It doesn't bother me because the lip colors I wear are pigmented, but this might work for my nudes.