Phone won't charge and isn't recognized by computer after water damage

Water Damaged Iphones can work for a few hours, days or even months after water damage. It is best to have it tested by a reputable Micro Soldering Tech as part of a circuit or circuit(s) could have shorted out to ground. VCC_Main, VCC _Bat, or the Charging IC's Tigress and or TriStar (U2) IC may have to be replaced as well as being cleaned in an Ultra Sonic Cleaner.

Even after the repair, your phone may never work correctly again as corrosion will progress under IC Chips...but if you are interested in Data Recovery, many techs can get it cleaned up, working and retrieve this data. Get you back the phone working but no telling just how long the repair can last.