My Leeloo can´t eat apple or she gets mouth sores at the corner of her lips. At some point, Nookie had them too. I´m not sure this is the same thing as described by Renee, but mouth sores take forever to heal. I used Methilene Blue on them, as it dries the sore and makes it crust over.
Renee, could it be an allergic reaction to something?