I'm using acretin to my body acne, is there any advices for better results?

Switch to tretinoin: I assume you meant acitretin, which is primarily used for psoriasis, which is very different from acne, so you wouldn't expect it to work well on acne, and it doesn't, in my experience. Tretinoin (accutane and other brands) is the proper retinoid for acne. Make sure the person prescribing it is a member of ipledge and knows how to use it. And be very careful not to get pregnant - with either drug.