so our DD got her 4 months shot yesterday. started to have a low grade fever in the evening and shot up to 102 F later in the night. we gave her 1 dose of Tylenol (half of 125 mg/5 mL) and it went down to around 99 F. obviously a reaction to the vaccine. fussier than usual and not eating much. how long does this last? reason to go to doctor if body temperature goes over 102 again? thanks.