I believe I have both normal lip chelitis (where the lips themselves peel too much, sometimes crack) and angular chelitis (that is where there is a crack at the corner, right?).
Right now I"m at 12 weeks, and my cracks at the corners have been flaring. I have noticed for the angular, it seems that it happens when I consume too much simple sugar in my diet. Normally I don't have this angular chelitis, but then it'll show up and I'll realize I sugar-binged that day. So maybe it IS yeast, because sugar can cause that yeast imbalance in the mouth. So probiotics may help, that, or just cut back on the sugar in your diet too. I notice for me, coconut water triggers it (That stuff has a lot of sugar, even though it's natural)....or just plain old sugary candy, like the gummy fruit slices covered in sugar. I ate both of those recently, and now I have this. It shows up the same day, or a day or two later, depending.
The other chelitis does not seem to be linked to sugar, in me. My lips seem to peel a lot, and I noticed it is better when I am taking a lot of B vitamins in general, especially B12. I used to do B12 shots, and when I stopped them, I noticed my chelitis started up again. I take B12 oral supplements, in addition to what's in my prenatal, and my OB okay'ed it. Though sometimes it is there regardless, so sometimes I suspect other B's are at play too. I have never tried B2 so can't say one way or the other. I have heard it could be folate too, so maybe you could increase that.