My 8 month old has always had red cheeks that seemed dry since I started giving him formula, I was told it was baby acne, now it is no longer raised but feels dry. Now he has large red splotches in his armpits, and then smaller ones on his tummy, side, and what almost looks like a burn under his diaper area. He has had diarrhea for 6 days now. Do you think he is allergic to something?