First thing to do is stop, but since it's unrealistic to go cold turkey due to physical withdrawals. I know of at least three friends of mine who have successfully used Methadone to stay clean long enough to make it throught the worst of it, and it wasn't that difficult to get.
If you are lucky enough to have the choice, I would suggest that you take your oxycodone without the tylenol in it, such as by using oxycontin, if it's available. The tylenol in percs is what is really damaging to the liver from what I've read, so taking oxycodone without acetaminophen it in would go a long way in aiding your recovery. As a general rule, the smaller the pill, the easier on your liver it should be.
But this thread did bring up a question in my mind that maybe someone could answer for me, and you may think I'm dumb for asking, but I'm going to ask it anyway. Do injectables get metabolized by the liver, meaning they put stress on the liver that can damage it? I thought I was doing allright by just not taking orals, but am I wrong?
I should know this, but I don't.
Anyway, Good luck with your recovery. You are not alone in your battle with opiates. If you're strong willed, you can overcome it and be proud that you did.