I know of a P.A. who did general practice and couldn't smell. He did
just fine.

Like Heather, I am a nurse. Like she said, sometimes it is a real
blessing not being able to smell (particularly in my field of psych!),
but other times I know that I can miss things that I would catch if I
could smell. Many times I have been asked if someone smelled like
alcohol or marijuana and I haven't the faintest clue. Someone could be
sitting right behind me and light up a joint and I'd never know.

Don't let your anosmia stop you from going into medicine. :)