Hi kmate, welcome to the community
Let's try to get your panel back.
The easiest method is to
- press [Ctrl]+[Alt]+[T] to open a terminal.
- in terminal: Type
mate-control-center
- in mate-control-center select 'MATE Tweak'
- in mate tweak: select
panel
In this window you can select a panel layout which puts you directly back in business.
tip1
You probably want to customize the panel a bit.
It might be a good idea to save your customized layout in mate tweak
Because if it happens again, you can call your customized layout directly with the steps described above.
tip 2
You also might want to lock your panel so that you can't delete/destroy it again.
The easiest way is from the terminal
To lock the panel:
gsettings set org.mate.panel locked-down true
To unlock the panel:
gsettings set org.mate.panel locked-down false
But you can also do this from a GUI like dconf-editor.