Brief Answer:
several possibilities can be there..thorough evaluation needed..

Detailed Answer:
Hello xxxxx, Welcome to HCM,
I've gone through your query and understand your concern,

First of all, please note that 20 days old symptom is really not an indication for any surgery..

However, can you please upload/attach the printed report/ a snapshot of the endoscopy report so that I can take a detailed look at it- which will help me to guide you more specifically ?

You can simply upload it at the reports section, alternatively you can even e-Mail it to YYYY@YYYY by keeping the Subject as ATTN:Dr Arnab and I'll receive it..

Also, do mention the Age/Sex,

Is there any associated fever/ headache/ sore throat/ ringing in the ear or any other concern ?

Is this the first time this has happened ?

Any other past/present medical/surgical ailments ?

Are you particularly allergic to any dust/pollen/ any other substance ?

Any history of Bronchial asthma ?

All those symptoms, i.e. green/yellow secretions are primary due to infection (most likely bacterial infection of the upper respiratory tract, para nasal sinus i.e. Sinusitis)..if not happening persistently, then pretty well manageable with proper antibiotics and decongestant therapy etc.

Please let me know which antibiotics were you prescribed along with the dosage so that I can guide you further in this..is there any other medications- please mention if any..

5 days of antibiotics is really short, and in chronic cases, antibiotic therapy of even 14 days or even more should be continued based on the type of the infection, organism involved, severity of symptoms etc.

Yes, please go ahead with the Allergic panel testing as it'll provide proper data to which your specifically allergic to..

Nose surgery or not, is depending on the further findings, complete clinical evaluation, detailed history etc. So please feel free to share these valuable details so that I can guide you more specifically in this regard..

Meanwhile please start taking Steam inhalation three to four times daily, it'll help with diluting the secretions..

Stay well hydrated by drinking a lot of water(~3 ltr per day)..

Awaiting for your response..

Take Care
Kind Regards

---