The sense of smell is at times affected by this type of surgery so your complaint is not unusual. It usually is permanent and the loss is not usually complete loss but rather partial. Ask your ENT to follow up and if he believes that further surgical intervention is required then go with it although I would advise that you get a second opinion first. Further surgery is not usually warranted but your ENT knows your case the best.

It is difficult to say how likely it is to recur. It depends on the situation and the patient. If the patient is experiencing chronic rhinitis or sinusitis due to the environment then recurrence may be likely. Chronic steroid use may be recommended to reduce the chances of a polyp developing. Like I said, it just depends on the individual case though.