Hi sossypops, I never have a nasal biopsy done but had nasal surgery before. I guess like for all other biopsy, they only remove a tiny bit of your tissue. Sometimes, more tissues from different locations/spots might be taken to cover a larger area for testing. A needle like instrument will be inserted and then the doctor will press a 'trigger' and the tissue sample is collected into the needle. But there are also other ways to do a biopsy.
Since your biopsy is done under GA, you shouldn't feel any discomfort during the procedure or know anything that's happening
. After you wake up, you might feel sore in the throat from the tube and nose will feel sore for maybe a few days. There should be minimal bleeding. If there's a lot, there might be packings in your nose to stop the bleed but I doubt that will be the case.
Usually biopsies are done with local anesthesia, not sure why yours is GA. So since it's under GA, your body will also need to recover from the effects of GA and the time differs from individual.
I also think your doctor will ask you not to blow your nose to prevent nose bleed. Well, it would be good if you could talk to your doctor or a nurse about the biopsy. Hope my 2cents help a bit... Good luck!