Can prednisone treat acne?

my dermatologist gave me a prescription for prednisone to get rid of some of my acne. i take 20 mg for 2 days then 15 mg for 2 days then 10 mg for 2 days then 5 mg for 2 days. he said i should have quite a few of my acne bumps go away. will they stay away or will they come back right after? and that small dosage for such a short period of time wouldnt have any permanent effects on or testicle size would it?