L.M.
Hi Y.,
Did the pink patches crack, then turn into sores? Are her lips really chapped too? Have her lips been itchy, or burning? There's yeast that occurs naturally in your mouth and it could just be overgrown- and she licked her lips and essentially gave herself "athlete's foot"- but on her mouth. If she's recently had antibiotics, or been sick, this can disrupt the balance in the mouth and cause this. This made the rounds in my family and if you think this is what she has, you can save yourself the time and money of going to the Dr. with a simple at-home remedy. Buy some OTC athlete's foot cream (I like the one for ladies, it has pink and smells a bit better) and the ointment (vaseline-based) version of an anti-itch cream with cortisone (mild), just mix a solution that's half and half of each and apply it to her like lip-balm. Just make sure she doesn't eat it!! You can apply it as many times a day as necessary- it'll also take the burning or pain away that she feels. You may want to check with a Dr. anyhow- but we had a similar problem in my family that a Dr. diagnosed and we used this at-home solution when it reoccured. I would also replace ALL toothbrushes and wash everything she eats/drinks off of in the dishwasher with HOT water.
Good luck to you!!