This study is a randomized controlled clinical trial designed to compare the efficacy and safety of two different cumulative doses of Roaccutane (isotretinoin) in patients with cystic acne. Participants are randomly assigned to receive either a total dose of 120 mg/kg or 150 mg/kg of Roaccutane over the treatment period. The primary objective is to determine whether a higher cumulative dose reduces the rate of acne relapse one year after completion of therapy. Secondary outcomes include the assessment of adverse effects and patient satisfaction. The study aims to identify an optimal cumulative dose that provides long-term remission with acceptable tolerability.