It was that gasp that Jensen made that made me think lung, but then he said goodbye to Sam for 2 hours so now I'm not sure. 😂 I thought any second he would spit up blood to indicate serious injury like they always do on tv and such. After looking at Sam's awful old man makeup, maybe they had already blown the makeup budget for the season or kept the makeup people away out of Covid fear? Either way, still obvious Dean got stabbed through something impotant. It wasn't like oh no, my gall bladder.