I'm not entirely sure how that works out. I'm guessing it might lessen the cycle of drying out and re-moistening the wet/dry border to an extent. However, it is impossible to prevent inner lips from getting in contact with saliva sometimes (and thus re-moistening) even if you constantly mouth-breathe because when talking and eating , your lips have to touch. Also, constantly mouth-breathing alters the hydration level of the whole mouth so can't be particularly helpful. If you do a google image search of 'lip competence' the second and third image of 'incompetent lips' look like they have mild exfoliative chelitis.