Hi, thank you for asking healthcare magic. I have gone through your query and understood your concerns. The blisters that the child had on the tongue might have been caused by primary herpes virus infection, and following treatment with antibiotics (probably broad spectrum antibiotics), the normal bacterial flora in the intestines might have been altered leading to diarrhea and vomiting which can lead to dehydration (more dangerous). What you need to do here is rehydrate the child with oral rehydration salt if the child can drink. If the child cannot drink or diarrhea persists, your take the child to a Doctor for proper assessment and management. I hope that answers your query. If you have more questions or any follow up query do not hesitate to write to us. I wish you well