Definitely Blistex and it must be the one that comes in the little white, round tub. It's amazing stuff, I couldn't live without it. Sounds like a vitamin deficiency and ironically, a lack of folic acid can be to blame for cracked lips. Are you taking your preggy vitamins? Get some extra folic acid from green leafy vegies, bananas (great for split lips!), peanuts and avocados.

If it continues, I would go to the doctor. I had a terrible case of split lips in my late teens which required a special antibiotic ointment.

Hopefully you'll be on the mend soon!