zeily cottonmouth dillan
zeily you said you get crust where lips gets split from using giab.
i think that there is a bad fungus or bacteria in mouth and when it touches lip tissue, body makes keratin skin layer over the lip to protect the tissue from infection.
in split part of your lip from GIAB bad fungus or bacteria is able to touch lip tissue, so is body making keratin skin layer continuously to protect lip tissue on that part of lip. you don't have crust formation on that parts where lips don't get split and where possible bad fungus or bacteria cannot touch lip tissue as GIAB works as barrier by not allowing possible bad fungus or bacteria to touch lip tissue.
if it is autoimmune caused than you, cotton mouth, dillan all will have dead skin coming out of the beneath the lip tissue even you putting GIAB on lips.
if jason, hopeforcure, anonymoushealer is reading this please give us update on your lips condition.