If you have any reason to suspect your phone’s internal components, including the battery, are damaged or wet, stop using your phone. Please note that liquid and physical damage are not covered by the warranty. Please reference your limited warranty for additional detailed information.
There are third party vendors that may be able to repair your out of warranty device such as Palco Telecom: www.palcocellphonerepair.com. Note that Microsoft is not responsible for the pricing, service, quality or completion of any out of warranty repairs by a third party vendor.