He is the luckiest snake ever. Vet said there was no spinal damage or organ damage (thank god for his mobile heart) and just bruised himself where he got stuck. Some loose scales but overall a clean bill of health. He suggested putting some sudocrem or flamazine on the affected area and keep an eye on it for any scabbing etc. Next time I feed him i might give him a smaller rat size too.
https://imgur.com/a/5v6YFzh
Bogertophis: I know, its 100% my fault and it had honestly never occurred to me that he would do it... There is a photo of his whole enclosure in the link, if there is anything you think is wrong with it let me know. The branches I have are 'Lucky reptile dark grapevine'.
Zincubus: In the end I managed to slide him back out the way he came. He stopped tensing up for a second which was just enough time to slide him back out, either way so so so lucky...
Thanks again for all your input, now I can go to work while he sleeps it off!