My phone says there is water detected in the charging port what can I do about that?

You can hope the water dries and doesn't cause irreparable harm, but water intrusion is often fatal and cannot be repaired. Let the phone dry completely, but if it doesn't resolve on its own, you'll need to have the phone replaced.

Liquid damage is not covered by iPhone warranty. Schedule an appointment at your Apple Store Genius Bar for evaluation and options.