How do I edit php pages within contribute

I have a page that I have made PHP.  The purpose is to display different parts of the page based on the subscription level of the client.  So there are 4 subscription levels and 4 section of the page.  Now I want to edit one of the 4 sections which are html code.  It displays the page correctly, however once I select edit the page is recognized php and shows a little box icon and not html.

I use contribute to edit the HTML portions of the page??

John  -