I have had one colonic irrigation, the therapist stated that I was in good shape and could stay on a maintenance program of once every two or three months. I know there are different schools of thought on this so I would talk to the therapist and get any questions you have answered.
Although I have done quite a few things in the last 15 months, I have cured (? hoping for no flare ups) seborrhic dermatitis, eczema, rosacea... uncontrollable itching and flaking among a hst of other ills (I can wear black again!!). I would point to bowel cleansing as the answer to this problem for me along with a greatly improved diet. I suspect a colonic would work to do the same.
I think that the colonic helped improve my skin some even though I had pretty much gotten a handle on skin issues by then.