I have found that sometimes just a small hit of something in the later stages or even peak stages of withdrawal, day 3 being in the peak part usually, doing a small shot of something actually may help me wean down a bit.
There has been numerous times where I had gotten arrested, or got hemmed up in a situation where there was no way of scoring at all, or getting a sub or anything. But one example is where I got arrested, and sat in city jail for a couple days in full dying agony withdrawal, and then seen the judge and he happened to cut me loose. A friend would pick me up from the jail and he would have something for me or we would go get it. We would get high or whatever, my WD would be cured, and then the next day I would wake up and be like whoa I really don't feel that bad, still a little shitty but not too horrible.
So sometimes just a little something to satisfy those receptors while in full blown withdrawal might actually help a little bit and act as weaning yourself down. It has for me anyways. So it may not put you back at square 1, but I'm sure it would if you went all out and used heavily.
Good luck getting thru it man.