Where did you hear that Muscle Milk gives "you" acne problems? I've been using it off and on for years and it never gave me that problem. Everyone reacts differently to a product it MAY or MAY NOT contribute to an acne problem for you. I love MM, in my opinion it's great. I don't want to tell you not to worry about it, and then you get it and happen to get acne lol. But I've never ever heard of this being a problem.
You're better off making your own homemade gainer anyway. Way better off actually. Cheaper and "cleaner" IMO.