As others have stated, bupe causes precipitated withdrawals in co-administration with opies. Next time research a drug before consuming it. Basic HR. This is very common knowledge regarding bupe, so this situation could've very easily been avoided had you bothered to even simply GLANCE at an information resource.
Your friend is wrong, it has nothing to do with your intranasal administration. And whomever told you (or the people you "heard of") that they dosed diacetylmorphine and buprenorphine together and got "fxxxxx up" were LYING. Lol this is just silly, the two are not a fun mix by any stretch. If you consider withdrawals a fun, fucked up, good time, then sure I guess....but most people do not, and I would not recommend it.
I apologize if I am speaking too bluntly or harshly, but this is just "DUH STUPID!" territory for me. The fact that people consume substances with which they have no knowledge of and are too lazy to be bothered to care for their own life, health, safety, and well-being by doing a little light reading is completely ridiculous and beyond absurd to my mind. Hopefully this experience will serve as a valuable lesson for you in the future- choose to learn from it. This could've been much worse. Good luck.
Regards,
-PA