The 'richtext' (wysiwyg) editor adds the <p> tags in a bid to output semantically correct HTML.
However, the content you enter into the 'textarea' and 'text' type regions should be outputted unchanged.
There is no reason why using the content from these two types mess up your layout.
Could you please view the generated source of your web-page and see what exactly is getting outputted within the meta tags? And how is the output different from what you had inputted in the admin-panel?
It'd help if you paste in here -
1. Your input in the admin-panel
2. The output you get on the web-page