I haven't heard of Milk Thistle causing Acne before, but I do think it might be helpful to have a series of colonics to get an assessment of you the condition of your large intestine.
I'm a practitioner of colon hydrotherapy, and you can tell a great deal about the clients overall health from observing the waste matter the client releases through the outflow observation tube.
If you haven't had colonics before, here's a picture of a modern closed system that shows the lighted outflow viewing tube.