Popping noise?

[AndrewM1217]

So I took my baby spotted python out today to mist his tank seeing as he is due for a shed soon, and I noticed him making a "popping" noise. I also noticed his neck immediately after his head seemed a little puffy or stretched like he had just eaten, but it returned to normal quickly while I was holding him. I checked his mouth and nose and couldn't see any sort of bubbles or mucus. Also he ate 2 days ago, although he didn't strike the way he usually does. He just sort of took it from the tongs and ate it. Although, it was a much smaller mouse than he usually gets so maybe he didn't feel the need to "kill" it. I offered a second mouse which he refused, and generally he is eager to eat a second meal.

Outside of this popping noise, he has been relatively normal. Somewhat lethargic lately, but I thought that might be because of the winter and also because of the shed he most likely has coming up soon (hard to tell with spotteds it seems, in his 4 sheds with me I've never once seen his eyes turn that telltale shade of blue). Anyway, no stargazing, still eating, still calm when handled, and nothing else really. Is this popping noise something to be concerned about?

EDIT: forgot to mention, I've seen him do that yawning thing a few times lately, even prior to feeding. I know they do it to reset their jaw after feeding, but once or twice I had seen him do this within the last week or so

[AndrewM1217]

So he just shed today, so i'll see if that makes any of the popping noise stop. I read somewhere (may very well have been on this forum) that sometimes that popping can be caused by loose shed skin covering the nostrils

[Tsubaki]

Could of easily been caused by the shedding, hope its over now!