You can restore a new Xfce panel from the Xfce Settings Manager. It can be accessed either from the context menu (right-click on mouse) or the run dialog.
From context menu: On Xfce Desktop, do right-click to open the context menu and go to Applications > Settings > Settings Manager
From run dialog: Press Alt+F2 to show run dialog, then type
xfce4-settings-manager and press Enter
In the Xfce Settings Manager, look for menu called Panel and click on it. If you don't have any Xfce panel running, a dialog box appear like screenshot and asking "Do you want to start the panel? ..." like so.
In the dialog box, click Execute. The result: an empty, new panel will appear somewhere on the Desktop (may be an unextended panel at 10% size). On the empty panel, user can do a right-click and click Panel Preferences... already.
Important: Save the changes before log out.
Ensure to select the option
Save session for future logins, then only log out. Log in again and user will see the panel remains intact.
Finally, the next time you log out, you should deselect/remove the option to avoid making unnecessary changes.