I took my Samsung Galaxy 4 for a walk in the pool, not good. worked briefly. Tried the commercial hand dryer, the rice to no avail. Was able to get it start up in emergency mode, following directions in a manual. but even that was short term.
So how do you pull residual moisture out. Tried this AND IT WORKED!! Removed battery from phone, reinstall the back cover, place phone, backside on top of frozen ice pack for an hour, then do again with another ice pack.
The extreme cold causes any residual moisture to condense on the cover.
Back to NORMAL!!.