Acne Coming Back 3 Months After Stopping Accutane?

I have just finished my second course of accutane 3 months ago (my first course cleared me 3 years). I started a second course because me acne was persistant but not really bad. Now, 3 months ago I finished a 4 month course of 30 mg per day but since a week my acne is coming back. Still not severe but annoying since I was clear for 3 years. If I start another course now, will it be necessary to do another full course or are 2/3 months enough since I just finished 4 months?