Phlegm and coughing of baby

My baby is 3 months old going to 4 months. When she was 2 months old, she was admitted to hospital due to high fever at 38 degree celcius. Doctor examined her and confirmed that its viral infection. Before she got her high fever, she was having blocked nose and coughing. When she cough, I can hear the phlegm and I guess it irritates her a lot. Even though I have given her Illadin nose drop, and her paedatrician has given her cough syrup(mucosolvan,XSP-Bena Expectorant), yet her condition is still the same. It has been 1.5 months and she is still suffering from blocked nose and phlegm.