usually if baby is still active, then it's probably fine. just maintain good hygiene - remember to always wash your hands aft handling diapers. however if it persists, i'd go seek clarifications from the doc. maybe reduce milk by abit first and see how it goes? did you gave paracetamol too?
For rotavirus you must maintain good hygiene, your child may either vomit or diarrhoea, if this prolongs, you may wish to visit the doctor again.