My lips are so oddly shaped that they affect my smile?

I've been self conscious about this for over 5 years and I STRONGLY believe it has held me back socially quite a bit. I know I shouldn't be complaining about trivial things such as this, but I think I can be/do so much more if I had a nicer smile. My teeth are straight and everything, however, my lips curve downward quite a bit and it looks very unattractive when I open my mouth slightly (my teeth don't show at all). I also have to smile really wide in order to show my top teeth. Is there anything that can be done to improve this facial feature?