Liver Flushes don't necessarily clear up bowel problems. She must do some bowel cleansing. I suggest she read some of the links within the link below. Read ALL about bowel cleansing (Journey to the Center of the Colon article for sure!).
Also, like Yemaya suggested, maybe some emotional/spiritual type cleansing would be good for her too. In Chinese medicine the lungs affect the skin. Lungs store grief and sadness. Do these emotions ring a bell for your sister? Her skin is trying to tell her something....it could be physical, but it could also be emotional - and some delving could unearth some stuff...then she could begin to heal!