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 >
From run dialog
Press Alt+F2 to show run dialog. Type
xfce4-settings-manager and hit Enter key.
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? ...".
In that dialog box, click on Execute button.
An empty, new panel will appear somewhere on the Desktop (could be an unextended panel at 10% size). On the empty panel, you can now make a right-click > click
Panel Preferences... already.
You will need to save the changes, by selecting the option
Save session for future logins, then click Log Out. Log in again and you should see the panel remains intact.
Finally, the next time you log out, you should deselect/remove the option to avoid making unnecessary changes.