Too much water for BRB?

[snakes_rule]

Hello, I have a two year old male BRB who for the past few hours seemed to be drinking constantly. I didn't desturb him because I figured he knew what he was doing, but then I got worried. I took him out, and noticed that he had a HUGE bump in his throat (I guess where they hold the water before swallowing), but I had never seen it like this before. He kept opening his mouth, then suddenly spat a bunch of water out. He did this a few times- once he would spit, the bump would be gone, but then it would seem to fill up, and he'd spit again. He did this about four times. Totally freaked me out! Does anyone know why he might be doing this? He seems fine now- acting completely normal. It's been about 13 days since I last fed him- I was going to feed him tonight. Could he have been hungry and just filled himself up on too much water? I don't know what to think...or do. I am thawing his mice now, and I will feed him when they're done.

Thank you so much!
Tess