hello and welcome to HCM,
Some amount of crusting after septum surgery is common and this may present as you have described.
In most of the cases self cleaning with salt water as advised by your ENT doctor is sufficient and just a course of antibiotics will do the trick.
However if the crusting is more and the odor is not relenting then your ENT must do a small procedure called the endoscopic nasal cleaning which can be done without general anesthesia
in the out patient setting only and he can clean out the crusts and secretions more thoroughly and completely.
Furthermore, the state of the sinuses
can also be ascertained.
Make sure that at least in the first one year you go for follow up with your ENT so that a proper symptom control is obtained
take care and get well soon
Dr Sriram Nathan