It is possible for a child who had an ear infection and received antibiotics to develop a fever again. This could be due to a different virus that the antibiotics cannot treat. It is recommended to consult a doctor if the fever lasts more than 3 days, especially for children under 2 years old. In the meantime, you can try nasal hygiene techniques and give appropriate medication like Advil™ or Tylenol™ to help with any discomfort and reduce fever spikes.