Over the past two days, my toddler has developed a sore on her upper lip. It started small, but now looks very much like what a "nursing blister" would in a newborn, and it is red and "weeping." Sorry if TMI! She has no other sores in or on her mouth, and does not seem to feel bad. She hasn't been sick lately. Do babies get cold sores? Does this sound like one? What is the treatment? We are headed out of town on vacation soon, and I want to treat this if we can. Thanks!