So after Pythagoras not eating for many months (actually since October 14) we visited the vet.
He has gone without eating before and has always decided on his own when to start eating again but it has never lasted this long.
The vet recommended vitamin injections and a force feeding, and when she said that is what she would do if my snake were hers, I rolled with it. After the force feeding and the massaging to make sure he kept it down the vet tech even commented that his moving forward was a good sign and that if he were going to regurgitate he probably would have done it by now. I pay, I leave, drive home (roughly 20 minutes) and in the time I go open the doors (to the house and to his enclosure) and come back to take him inside I can see the dark stain on the pillowcase. I would say that at least most of the mush they pumped down his throat came back out and there was even a tiny bit of blood mixed in (very, very small hint of red).

I feel terrible that I subjected him to that and I feel even worse that it apparently was all for naught. Of course I'm not happy that I paid over $160 for them to make my snake vomit for the first time in his life either.

Does anyone have any experience with a snake regurgitating a force feed?

I just feel sick right now and there is no way I can do nothing until I call the vet tomorrow morning. I already called the emergency vet but they just said keep an eye on him unless he looks much the worse for wear.