I have never been able to use Lac-Hydrin or any of the lotions with acid in them without having a lot of pain, regardless of whether or not there were any open sores or cracks. It could have been gas pains, but since it's happened twice now, maybe not putting it on her stomach from now on would be a good idea. Everyone responds differently to all the treatments, even when they have the same type of ichthyosis. And, people reactions to treatments can change over time.
I am female, and was born in 1972 with Lamellar Ichthyosis.