I came off a year of opiate pain killers. All kinds and any kinds. Let me first say as hard as it may seem...acute wd's aren't that long. Much like alcohol. Feels like an eternity...I get that. But it really will seem like a distant memory soon enough.
Stick with it and you'll be happy.
The pill you took will have its impact no matter matter what. If it's an opiate, then it's an opiate. Might not be as strong, but it will give strength to the monster. The best thing to do is push through and stop feeding it. Let it die.
You probably won't revert back to square 1, but it will take you back a couple squares. It's kinda like 1 step forward, 2 steps back. Don't be too concerned. That'll just make it seem worse.
Push through it. You'll be very happy you did.