Go for ncct pns axial and coronal cuts vitd3 ,cbc, aec, test
start metaspray 2puff twice daily in both nostril tab montair lc kid once daily all for 10 days.
Buy nasal blower for pediatric use and keep cleaning nose secretion. And use that nasal drop it will gradually settle ,if not then see a Dr. ask if needs further medication.
Keep the child well hydrated by adequate replacement of lost fluid by WHO recommended ORS and routine home diet with little added salt.If child is taking breast feeds continue with that. And wait patiently unless he is dehydrated( In that case visit hospital he might need IV fluids). It takes time to get well.Hope this helps