To show template path hints in admin panel of magento you need to login to your phpmyadmin then run the following sql command

INSERT INTO core_config_data (scope, scope_id, path, value)
  VALUES ('default', 0,   'dev/debug/template_hints', 1),
  ('default', 0,   'dev/debug/template_hints_blocks', 1)

To hide template path hints of admin panel or backed just run the top code by changing 1 to 0, then the template path hints will be hide.
You also can run the following sql command to hide template path hints.

INSERT INTO core_config_data (scope, scope_id, path, value)
  VALUES ('default', 0,   'dev/debug/template_hints', 0),
  ('default', 0,   'dev/debug/template_hints_blocks', 0)

If you have already activated template path hints in admin panel or if you already run the top sql command once then No need to run this code again.Just go to core_config_data table of your phpmyadmin then change the value of `dev/debug/template_hints` rows to 0 or 1 to show or hide.