The duration of a fever after starting to take amoxicillin for two ear infections and bronchiolitis can vary. Typically, if the antibiotic treatment is effective, you should see an improvement in symptoms within 48 to 72 hours, with a decrease in pain and the fever disappearing. If this is not the case after 72 hours, it is recommended to consult a pharmacist or doctor to reassess the antibiotic treatment. In the meantime, you can continue to monitor and control the fever by alternating between Ibuprofen and Acetaminophen as needed. It is important to consult a pharmacist for precise dosing and administration intervals.