Some snakes do consider a water bowl to be a hide if they find the hides you provided are in any way inadequate. Especially if the "cool side" hide is lacking. Are you saying he is getting too big for his hides? His hides should preferably be identical so you can tell that he's not choosing the "right" hide over the right temperature- so if this is true, he would outgrow them both at the same time.
Snakes can & do blow a few bubbles now & then from drinking water- it's like when someone startles you or says something very funny the moment you take a drink of water- maybe the bubbles were his reaction to seeing you suddenly nearby. So yeah, if you don't see any further issues, he likely just got water in his nose. Rubbing his head against himself (or on something else) is what many do after eating (instinctively removing the scent of prey) or after drinking if there's water in their nose/pits, for example.
What substrate are you using? I'd try keeping him on white paper towels for a while, & wipe over him with a damp one also, to see if there's any mites. Soaking is often the signal that they have mites- & mites are bad news, so you need to be sure, not wait until they do harm. BUT, mite "treatments" are not without potential harm...therefore I would not advise treating for mites unless you SEE them. "First do no harm" as they say...![]()