How do I restore a WordPress site?

I lost my site a few minutes ago after adding some code to the Thesis theme custom_functions.php file intended to remove all Jetpack Open Graph tags. After I clicked the Save button, my browser window went white and no site content has been visible since that time. The site is PC and Vladislav have been assisting me with the issue that led me to the present moment. The thread is at’t-my-post-images-being-generated-for-display-in-linkedin-updates?replies=17#post-414512