They are just trying to come up with some theories to justify the situation. The fact is that nobody knows why post-surgical shedding occurrs. So bear in mind that you may end up with less hair than before you go for the surgery. Post-surgical Swelling Almost at least half the patients experience swelling in their forehead and part of the face soon after the surgery. The swelling will last about three days to a week at most.
Nobody knows exactly why.
Some surgeons say it is because of the anesthesia. The swelling can get quite noticeable and it would be awkward for someone to go to work in that condition. There is no effective way to get rid of or stop the swelling. You simply have to wait till it diminishes. Most doctors will advise patients using ice on the swelling.