It's always a balancing act with meds because the liver processes everything, but just because you have liver disease doesn't mean you absolutely cannot take a statin -- depends on your circumstances. (Hopefully you have a cardiologist and hepatologist talking to each other... that would be optimal.)
My husband has had cirrhosis for at least 3 years, and he has simultaneously been taking a moderate dose of simvastatin (20mg/day) because of elevated cholesterol previously complicated by a near heart attack. He maintained that dose until just recently when treatment knocked his cholesterol down to unusually low levels (70s), so they cut his dose in half to keep in the the 100 ranges.
There was an older post about statin use in hcv patients you might find interesting:
Don't know much about post-treatment blood results, but I have read about other members here having rises in cholesterol post-tx. Hope that helps.