Please help me work on the Face ID
the phone was affected by water so the water made the Face ID to be disabled that very day
Question marked as
If your iPhone has been in contact with water, you will have to get it serviced by Apple or an Authorized Apple Service Provider and replacing it will be most likely your only option.
To get service, have a look at the links on this Apple page:
iPhone Repair & Service - Apple Support
Or find an Apple Store or Authorized Service Provider next to your place: