Yah acetaminophen damages the liver, not oxycodone so if you plan on doing more than 3000mg of acetaminophen which I will say is over 6 pills do a cold water extraction, search google or previous posts it is on here in several threads.
Smoking with it is fine, drinking however will cause more respiratory depression and if you do too much at once there is a greater risk of death.

Do not do oxycodone everyday, especially if you can't get Oxycontin or generics containing ONLY oxycodone or do not have the money to support the habit.
Physical withdrawal symptoms should not appear until ceasation following several days (a week) of consecutive use.