You have not told us which model iPhone you have.
iPhone 7 and later are water resistant (not water proof). Earlier models are not even water resistant.
As you can see here, even water resistant iPhones should not be taken into the shower.
This explains how to check your iPhone for damage. See "Find out if liquid damaged your iPhone or iPod" here:
Take your iPhone to an Apple Store or Authorized Apple Service Center. Let them assess it and advise you how to proceed.