Is it normal to have a fever in bronchitis AFTER antibiotics are started?

My 20 month old was diagnosed with bronchitis on Sunday. He only had a very low grade fever (about 100.4) that went away completely for a few days. They put him on antibiotics because he also had an ear infection. But now, 3 days later he has had a fever ranging from 100.3 to 101.8! It just won't go away. Is this normal?