Not that you would ever muck them up, but just in case:
Get a terminal somehow (alt+F2 if you must). Type this in:
gconftool –recursive-unset /apps/panel
(or, both if you like)
rm -rf ~/.gconf/apps/panel
that sounds like a lot of violence and killing and stuff, but it should work. Both of your panels will reappear like magic. If not, go here and complain because this is where I learned it!