My 7 month old baby has a ear infection and a 100 degree fever for the last 3 days. What else can we do?

Puzzling question. I assume you have seen a doc, since that's the only way to be sure it is an ear infection. I don't consider 100.0 to be fever in a kid that age. It is within the normal fluctuation in body temperature for age but may simply reflect a minor increase in metabolism as the kid fights the illness. If the kid is feeding well and playing some you have done all you need. Follow up with doc as needed.
What have you done? Has your baby been seen by its doctor? Is it still pulling at the ear? What medication is it taking? If has been treated by a doctor and continues with fever for three days, depending upon what else is going on you may want to bring baby back and have them re-examined.