L.G.
My son always got terrible diaper rash (and was very loose) when he was teething. I would call the dr just to make you feel better. Once I called the dr thinking my son was sick with a bug because he had had diarrhea for a few days. It turned out he was allergic to Ovaltene (sp). If he drinks chocolate milk made with that stuff, he gets diarrhea. Go with your gut.
Good luck!