My Doctor Thinks I Have Polymyalgia As Well As The

My doctor thinks I have polymyalgia as well as the lupus I have had for years. He has started me on a 25mg dose of cortisone, dropping down as usual in stages, if this helps this time what else will need to be done for the pain. I have had the blood test this morning will get the results next week. I would like to know once I have been told it is this didease will I have to keep taking cortisone?
Thank you
Irene