Backlight quit and button appears to be short-circuiting

This week, the back light quit coming on and the watch is constantly responding to the “long press” action. So from the home screen it’s continuously triggering an activity, then asking to turn itself off. I managed to shut it off once, the battery ran out another time. I’ve also updated the firmware, no change.

Swam with this weekly for over a year just fine, and swam earlier the same day I noticed this but was hoping it was a coincidence. Whether it’s water damage or not, what are the chances a teardown and/or part replacement will fix it?