To the OP,
I would not suggest buprenorphine to be taken daily for three months, if it is your wish to lower your tolerance to opioids, because buprenorphine is fairly well-known as a very potent opioid, and even if it is a partial antagonist, the activity it exerts as an agonist, like most classical opioids used in pain management, is very strong. The result of taking buprenorphine, with any regularity, will be an overall increase in opioid tolerance. So, the question is how can your opioid tolerance be reversed, while still taking enough of an opioid agonist (even if partial antagonist)? Well, this cannot really be done. What I would do, if I were you, would be to take a serious look at your situation, and get to know more about what causes your type of pain. I would then look into trying non-opioid drugs and non-pharmaceutical pain management (acupressure, acupuncture, yoga, progressive relaxation exercises, meditation, light exercise, etc.) WITH an opioid, such as the oxycodone you are currently taking. That would likely allow you, permitted you got on a good regimen for yourself, the possibility of slowly lowering your dose of the opioid to where you are continuing to enjoy pain relief, but where your dose of an opioid is lower, on the whole. Eventually, you would become comfortable with a lower dose of an opioid, which would mean, by definition, a lower tolerance. Now, such a tolerance could easily be shot right back up, so you would want to be cautious with how and how much you would reduce your opioid dose.
Now, I mentioned non-opioid drugs to help in pain management, and many can help alongside an opioid. Some people benefit from pregabalin or gabapentin, especially for nerve pain and fibromyalgia pain, but either of these could help with any pain, so long as your condition does not make these drugs potentially dangerous. Other non-opioids include anti-depressant drugs, and though I would advise to be VERY careful with any of them, I will mention, particularly, that lower doses of tricyclic anti-depressants often can help with certain types of pain, but again make sure, if you were to try any other drug, your health would permit for it without significant threat of risk, because it is always best to be safe. A few other drugs that might or might not work, depending on the source of your pain, include ASA/NSAID's, corticosteroids, and muscle relaxants. A particularly good muscle relaxant for the use of pain management, and one which does potentiate all of the effects of an opioid, is carisoprodol.
Another technique, which will allow your tolerance to crawl, but a bit more slowly, and which I think has some merit behind it, is cycling your opioid of choice - for example, switch from oxycodone to morphine, for maybe a month or two, then maybe try out hydrocodone (it is available, although at high prices, I've heard, in extended-release form, now) for a month or two, then back to oxycodone for a month or two. This is just an example of how it could be done. I will tell you, though, that this technique I would only give thought to, if you want to keep tolerance down as much as possible; it won't reverse your tolerance. Also, don't forget about what I said with respect to non-pharmaceutical approaches - you just have to find what works best for you, like with pharmaceuticals.
I am interested in your situation, though - the type of chronic pain you have, the pharmaceutical and non-pharmaceutical approaches that have worked and those which have not, how you use your oxycodone now (how much and when you dose), other suggestions your doctor has put forth or which he'd be receptive to, and most bothersome part about your pain (other co-morbid symptoms or otherwise)?
