What you are seeing is not related to the scent gland, as scent glands on snakes are posterior to the vent. I have seen a few cases of scent grand related abscess and they appear to not impede apatite or digestion of food items. I have seen 100% recovery through simple veterinarian procedures.

Want you have going on seems to be related to digestion and removal of waste products...I think related to a change in diet. It is possible that there is some sort of blockage (hair?). I've seen something similar to this in Emerald Treeboas, and in that case they seemed to have developed a large uric acid mass at the base of the cloaca - which was carefully pushed free if not too large.

That is about all I can say of your issue, post back when you figure it out.

I would immediately seek assistance from an exotic vet.