19mo old has rash on face around mouth after eating cottage chz & cantaloupe. She's eaten these foods before but not usually this messy. Any concerns?

Could be allergic. Allergy typically requires a-repeat-exposure to have the reaction. Since the child is getting the rash, it is seemingly just localized, at least for now, from the use of the above--cannot tell which one. Or, it is simply from rubbing/cleaning the mouth too much can cause irritation. Can try one at a time, don't clean too hard, and see which one causes the rash.. Check with your doc.. Good luck..
Food Allergy. Babies gets irritation from food easily if not cleaned at once.Apply hc 1 percent around mouth to treat the rash. If rash reappears after reintroduction of the same food, it could be food allergy. Remenber some food allergies are serious.