Regurge? Retained Fecal Matter?

[Zythen]

First off my snake went blue 3 days ago, so I knew he was going to shed. Now I've read that they can be irritable and refuse food when they're going to shed. He was neither of these, very docile and then eager to feed. I fed him 3 pinkies like I have every Tuesday for the past month. I fed him around 1PM. Around 11PM we noticed that he had shed, while removing the shed I saw that there was some black stuff in the corner beside the shed. It kinda looked like fecal matter and the would actually make more sense, I wouldn't think a regurged pinky would be deteriorated and black in just 10 hours. It was a very small substance and he still has pinkies in him. It doesn't look like any of the three are missing, and these were large enough that you can tell their in there. So what would I follow for this situation? Do I consider it a regurge even though I'm not sure? Could he really have been holding his fecal matter for that long?