Not something I have experienced, but a number of the other meds like levalbuterol can also cause this. When I am using nebulized meds., or if I get mouth sores from something else, I use a mouthwash for sensitive and sore mouths - which one I buy depends on what the local Walgreens has at the moment.
And sometimes, I lean on old-fashioned Lavoris, which contains cinnamon, anothrer soother.