Airplane travel - advice needed

To anybody with any knowledge on this subject advice is amazing, i have just undergone a turbinate reduction surgery in my nose. i was told by a doctor when i booked the surgery that i would be okay to fly two weeks after i have the surgery. Im a healthy 19 year old male 65kg so its not like i have any underlying health issues or anything. i have now had the surgery and they are telling me that its 4 weeks i cannot fly for, i have read online and many places suggest two weeks also. i dont know to chance it or to cancel it as two weeks seems like plenty of time to heal. i have had a look on my travel insurance and as i booked the operation before i got the insurance it is seen as a pre exisiting condition so theres a chance they might not cover cancellation ( i know insanely stupid to not get it beforehand but hindsight is 20/20 ) any advice is appreciated thank you