Want to ask about post nasal drip. This?

Hello, i am suffering from post nasal drip since last 1-2 months,i had consulted a ENT surgeron and followed his treatment and completed his course for sinucitis.but i didnt got the full relief after his treatment especially in post nasal drip.he only had given me a Common cold medicine and Silent reflux medications.however i didnt got full relief after his treatment.So i tried otrivin oxy relief adult nasal spray for 3 days in a row i got relief from it.but after taking a break from it for 3 days my symptoms came back.i got relief after using 3 days constant in a row for 3 days. So my question is "Can i use otrivin for 3 days in a row? Then take a break for 3 days and can use it again for more 3 days?" Can i use like this pattern? Will it cause rebound congestion if i use like this?