In your Dashboard view, on the upper right corner, under the “[name]” is a tab labeled “Screen Options.” Click it. Here is a list o the screens where the modules can be hidden:
Posts – Post Tags, Categories, Excerpt, Send Trackbacks, Discussion, Comments, Post Slug, Post Author, Post Revisions
Page – Page Attributes, Recommendations, Featured Image, Discussion, Comments, Slug, Author, Revisions
Select those and return to your Dashboard.
Make sure you select Select Post Revisions and Page Revisions those and return to your Dashboard. Then close the tab.
On the left toolbar, click on either “Pages” or “Posts” depending on what type of document are you are trying to restore.
You can look the last autosave for Posts » Post Revisions
You can look in the last autosave for Pages » Page Revisions
For more see > http://en.support.wordpress.com/pages/page-revisions/