you are doing great till now and i would like you to continue with the same treatment for now as its like a viral upper respiratory infection
that will subside on its own after taking its time, whether you treat it or not.
but you must be watchful of some danger signs like rapid respiration, high grade fever
, excessive irritability or lethargy
, refusal to feed etc and take urgent advice in these cases by your pediatrician
you can use the cold
medicine (oral drop you mentioned) if the nasal catarrh is much trouble some, in dosage prescribed by your doctor.