(Concern) My child's lips are only dry. What's the solution??

My skin is just an average type, so as long as I carefully apply lotion after showering, I don't usually have major skin problems.ㅜ

My lips are particularly chapped and turn whiteㅠ I keep applying lip balm frequently, put it in my bag, and tell myself to reapply often, but there's no improvementㅠ Red lips look lively and prettyㅠ Our child is an energizer, but her lips are white and cracked, and she can't even eat properlyㅠ She takes supplements well and eats three meals a day, but maybe saliva is the problemㅋㅋ It just won't stay moistㅠ I'm worried that there might be another issue besides salivaㅠ