Think of it this way, a bite from a ham isn't going to kill you, it's not venomous and you won't die. I own Mexican Red Knees and they're a different story.
Maybe it's a little bit of cage aggression, or he was grumpy you woke him, he could be having an off day, lots of reasons. I wouldn't worry too much and just carry on as normal.
Ps: you kind of should change their water every day.