8 hours is pretty soon to be in withdrawal. Even heroin, an opioid with a very short-half life, didn't make me go into bad withdrawals until about 10-12 hours. I kicked it with suboxone, but remeraber, that is also an opioid and eventually you'll have to come off of it and withdraw from that as well. That I am dreading. As far as pain control, suboxone has been used to control pain for some reason in very tiny amounts. I'm not sure if the amount used to control pain would be enough to stave off craving for other opioiRAB, but be sure to discuss this with your doc.
Also, do your own research on the internet about suboxone, read all you can. A lot of doctors do not know as much as they should about suboxone and its correct usage and doses. My doctor's solution is always just to up my dosage, to ridiculous amounts that are unnecessarily large, from what I've read online. So just make sure to educate yourself. Good luck, check back and let us know how you're doing/what you've decided.