I have to agree with Steffe on this one. No other signs and it was clear. I bet he just took a long drink and you disturbed him by taking him out. They dont drink often and when they do they will take a very long drink. You took him out and his drink probably just came back out. Watch him closely for a couple weeks. If you see or hear no other signs he is fine. Have you looked in his mouth? Its very easy to open the mouth. Hold him firmly behind the head. Just grab the loose skin under the jaws between your fingers and gently pull down. You wont tear anything or hurt the snake. If the mouth is clean and a light powder pink with no bubbles, streaks or discoloration, he is most likely fine.