It is possible that the charging circuit is fried, experiencing problems, or that the cord may be bad. Try a different cable before anything else. Hope it was the issue! Ian
The pool situation could definitely cause problems and I doubt that the Mic is an exception. I'd try opening the device and checking for any water damage -
As someone who has an exact phone, but has never experienced this, I'd recommend contacting LG's support and or speaking with the group who sold you the phone. -