|Talk to your doctor about your concerns.
Taking prednisone for a shorter duration can cause a rebound rash much worse than the original. If you search on this board for "rebound rash" you'll see some links to papers from noted doctors about the issues with taking prednisone for too short a period of time.
So... you have to decide what is best for you. The side effects of prednisone or the potential for rebound rash.