It can take quite a bit of time to heal up from what I have heard from athletes. Just listen to your body and don't rush back. You can certainly continue to train other parts of your body though. Just be careful with legs.
i hate to break your heart but only rest can fix the problem once you have it
the key is NOT getting it in the first place.. proper shoes and not over training is going to be how.. i would run barefoot on grass in the first place.. people who run on hard surfaces are itching for problems
and as far as your question why do you need to quit the gym? there are plenty of lifts at the gym you can do even with plantar issues. it is running that you need to stop
Good to know. Just recently got diagnosed and I want to switch my shoes immediately. Don't want to stop running for a long time. Can I ask what shoes you use?