My BCI did the same thing I eased his mouth away and got out of there quick when he released. He didn't feed for a couple of weeks but then he was ok.
I've seen this happen a few times and it isn't normally too much bother. My old boa did it once, and my royal, and my king manages to attach himself to himself once or twice a week. He started to make an Ouroboros once, it scared the hell out of me (and made me giggle a bit).
I'm sorry and I don't mean to offend you or any thing but that first picture of your boa looks like he's committing the ultimate snake fail, and his face almost looks like he knows it.