My daughter's cough got worse after taking Prednisone. Why?

Hi doctor,

I have a 2-year-old daughter. She suffers from a cough for the past 17 days. It is nonproductive, and it gets worse when lying down. During night time, it comes as a dry hacking cough. The illness started with nasal congestion, and quickly, it became a cough. There is no rash, no changes in bowel movements or urination, or energy level. She has undergone tonsillectomy and adenoidectomy before ten months for sleep apnea, and it was successful.

She gets this problem for the past six months. She does not have a fever. We used steroids before these events. Now, her cough got worsened for the past two days. We consulted a pediatrician, and she was given with Prednisone 15 mg two times a day and Augmentin. I gave steroids to her.

She woke up in the night and had vomiting two times. She had a fever of 104 degrees Fahrenheit. She also had congestion. I consulted the pediatrician. Currently, she takes Zofran 4 mg, Ibuprofen 10 mg, and Augmentin. Does she have a new viral infection? Why does her cough got worsened? Is it due to a progressive lower respiratory bacterial infection? Is it due to a drug reaction to the steroid?