The hot tub might make any wounds swell, so that part is up to your better judgement. I guess you should just disinfect your belly button every time after partipating in these events, and make sure to take the ring out to clean that too. I went swimming after getting my ears pierced, and the only thing I noticed is that my earrings started to smell because of the moisture not evaporating. Maybe you could use a waterproof bandaid, but those don't usually work.