My son is 4 years old. I took him to the doctor yesterday for a bad headache, fever, loss of apatite and sore throat when swallowing. She tested him for strep and it came back negative in the office. She said it could be mono. He was treated for the strep with amoxicillin. Today he has blisters on the outside of his lip. One right below his lip, one right above, and one to the left of his lip. The doctors office still hasn t returned my two calls. Any idea what he has?
He is having Herpes labials. This could sometimes be associated with meningoencephalitis which is a grave disease. Headache nausea vomiting Chat Doctor.  Immediately start the baby on Acyclovir. I can't give you the dose as you have not mentioned the weight of the child. Starting the baby on acyclovir as early as possible is required.