How To Get Rid Of Black Lips?

Hello, I am a 16 year old female. When I was about 12 years old my lips started to turn black. Now they are becoming a issue for me. Its like I've tried everything. My doctor gave me a eczema cream for it but that didn't work. She told me use Vaseline also. Then I tried Ambi the fading cream, that hasn't seemed to do anything either. The newest thing I've heard to do is scrub my lips with sugar and honey. Can you please give me a working solution!!! :(