if it is not detected on your iOS devices or computers the the drive may be bad. In this case the drive would need to be replaced. If you need data recovery you could send it to a company that provides data recovery services.
If you used the iXpand Drive app to delete the pictures they may still be on your phone. iOS only allows third party apps to send deleted pictures to the recently deleted folder. If you have not permanently deleted the pictures from the recently deleted folder you may be able to restore them. After 30 days IIRC iOS will permanently delete anything in the recently deleted folder.
