Yeah there still a few more things that you can try, braining, puncturing the stomach, and if worse comes to worse, once you have been shown how to properly do it, force feeding. Next time you try feed him, try quietly sitting the pinky on the floor of the enclosure close to him, cover him and leave him alone, he might have been stressed by the hassling and once you put it down that may have stopped him having it. The other possibility that i haven't thought of untill now, and i dont wanna stress you out, but sometimes there could be a medical reason for it, like an abcess in his mouth or something like that. I've never had anything like that yet, touch wood, so i dont know what the symptoms to look for are. I have a thermometer in each enclosure before i put a snake in there, and at my local rep shop they have the black round ones and then single probe digitals for about the same price, but the digital are alot better i think. You can also get twin probe ones to monitor warm and cool end temps.