there is nothing to worry about in this case. prominent bronchovascular markings is a normal finding in medial 1/3rd of lung fields and so consider it a normal report and don't try to read between the lines.
this seems to be a case of viral respiratory infection
and it should go by 1 week or so.
the only thing you have to take care is about some danger signs like, respiratory difficulty, intractable coughing, cyanosis
, high grade fever
not responding to regular antipyretics, excessive ittitability or lethargy
so rest assured and follow the prescriptions of your pediatrician
hope my advice helps you
wish speedy recovery of your daughter
Dr. Amit Kumar