How do I moisten my lip corners? (Dry from Accutane use)?

I'm on Clarus (accutane) for acne for another 3 months, and it dries everything up. I have really bad lip corner cracking and chapping, it turns red with a crusty white. I keep putting vaseline patroleum jelly on it, and it helps it at the time, but when its off, it goes back to normal. I've tried polysporin and other lip balms with no help. What should i do? I cant wear a thick glossy cover on them while in public...taht just looks weird