Is The Non Healing Split Bottom Lip Related To MS?

Around Feb, my bottom lip split open and it still will not heal! It's right in the middle of my bottom lip and no matter how much lip balm I use, it keeps cracking open and bleeding. It hurts to eat cause I can't open my mouth wide enough without my lip popping open again. I have MS and I'm,wondering if it's taking so long to heal because of that. Please help!