Hi, Welcome to Hcm, Betnesol every month is suggestive of a need for long term prevention therapy. Post nasal drip xsn be due to allergic irritation in your child. You need to take certain measures at home to avoid allergen exposure like wet mopping, prevent smoke at home, avoid ice cold foods, washing and sun drying mattress twice a week atleast. Place the child at night sleep with head slightly elevated around 30 degress which will reduce the drip. For long term, I feel you need to start on preventer medications like monteleucast but better to consult a pediatrician and get evaluated properly again before starting that. Hope the view helped. Happy to clear any further query. Take care.