Oh my. First of all you need a hug.
There is an injury called ”degloving” which happens in a lot of animals in cases like you’ve described and in cases where the animal has gotten their arm or leg caught in something sharp and struggled until they were free or under the tire of a car.
Essentially it is where the skin is stripped off an arm or leg leaving everything under the skin (bone, muscle, tendons, blood vessels, nerves etc) intact. Thus the SKIN is pulled off “like the removal of a glove”.
This is not degloving.
Imho, This injury has stripped everything that would potentially keep everything from the top of that injury down, alive.
Therefore the only treatment option I think is even a viable one is to amputate that wing.
There have been BYC members who’ve experienced this injury with their birds. A few have actually amputated the wing themselves successfully.
Others have sought out the expertise of a capable veterinarian.
I have had a lot of medical and veterinary experience, but even I don’t think I’d attempt a “diy amputation” unless the bone was shattered and barely hanging on.
I urge you to keep the bird safe and warm and comfortable and well hydrated and encourage eating while you explore and investigate your options.
I’m hoping that others will weigh in on this as there are as many opinions as there are experienced and valued members here on BYC.