Its -40 to -50 where i live some days, skin is getting super dry and irritated with bp, the redness is getting pretty out of control some days. Does BP really need to be left on for so long in order to oxygenate the skin and kill the bacteria? Or can I leave it on for an hour or two and then rinse it off? I know this can be a hard question to answer since theres probably been no scientific proof to show how long it takes for BP to actually oxygenate the skin, and everyones skin is different. But does anyone have any input or advice, anything you've tried similar to this that has worked?
First of all, where the heck do you live? 
Now on to your questions. The important factor before we can make any assessment is, how bad is your acne? I would imagine that you'd do everything possible to stay indoors, right? Maybe invest in a couple of humidifiers to help combat the dryness. If your acne is bad, the BP needs to stay on.
haha i live up in northern ontario canada, so as you can guess this time of the year it gets pretty cold. my acne is probably more moderate, but the bp helps to keep it very under control, maybe at the most a handful of pimples a week, but if im using bp twice a day throughout the week even less, only problem is my skin gets super red. i do use neutrogena oil free moisturizer for my skin, but it doesnt help with the redness at all
Dont rinse off the BP unless its used as a face wash. Use a very moisturizing... moisturizer for sensitive skin. I HIGHLY recommend you try Olay Sensitive Moisture Therapy Lotion, i started using it and it makes my face very soft from literally flaking off because of BP and other stuff i was trying. It smooths on very easily, is totally clear, not oily at all, doesnt dry up after a while. It also helps fade acne scars and im sure it will soothe your skin to take away the redness. Its only like $7 anywhere and should last for atleast a month.
BP always really dries up your skin and makes it possibly sensitive to touch and etc., it happens to everyone, but as long as you keep applying good moisturizer, itll be fine during the time it takes to get used to the BP. Even after a couple weeks, keep applying moisturizer or it will get very dry and irritated again, remember, irritation=acne.
Hope i helped!
You can try adding some jojoba oil and AHA to your routine and get a humidifier in your room if you don't have one. I'm from Toronto (yay Canadians!) and the recent cold blast gave us some -30 temps too haha, but only for a week so. I can't imagine -50...
Good luck 
And stay warm!!
thanks alot. i will try that. i have been using moisturizer a bit here and there, but definitely not enough, i didnt realize it helped with the redness so much. will try that. thanks again
Yeah, make sure you use moisturizer everyday. It is equally important as the rest of the regimen (if youre doing it), it is very important just by itself too especially if you are in cold and dry conditions. Just make sure you use it twice a day and you wont need any other stuff like oils or a humidifier, no need for that extra complications, steps, costs. 