What Are The Side Effects Of Acutret 20?

Hello,i'm facing acne on my face and head .. though the head acne is getting worsed day by day so i consult a dermatologist on August 2010 and he gave me acutret 20 and asked me to use it for 45 days. I Used it and
got resutls. The Acnes are gone. But now the acnes have occured again on face and head. I contact that dermatologist again and he told me to use acutret 20 for 60days now. I want to know what is the side effects of acutret 20. I see that my lips r getting dry. Please help me out. Thanks