Rather than a lip mask...
These two have always worked for me, as I get super amazingly ridiculously pain-in-the-assly dried lips, especially in the winter.
1. Aquaphor
it's kind of like vaseline, but for me absorbs and softens my lips way better than vaseline ever did. It's also inexpensive and easy to find, and great to have on hand anyway for the occasional dry skin patch...or dry feet, elbows, etc.
2. This is by a company called Vichy Laboratoires. It's called Nutrilogie Levres, intensive care for dried out lips. I just recently got this at a CVS (pharmacy) for $11, and it's the best $11 I've spent so far this season. I put it on before bed every night. I like it even more than the Aquaphor; it's lighter but seems to deeply moisturize even better and more quickly. I now put this on (a little heavy) every night before bed and then gently slough off my lips in the morning. It's worked like a charm.