Re: Tiki site not visualizing after putting some code
Use phpmyadmin to access your Tiki database. The code you added will be found in the tiki_preferences table, so browse that table. If you added the code to the "Custom HTML <head> Content" section under the "Customization" tab, the "name" column will contain "feature_custom_html_head_content". Delete that row and it will remove the code you added.
I just tested this and I also had to clear the cache before the delete took effect. So, if you still have the problem after deleting the code through phpmyadmin, access your site using a different browser (if your usual browser is Firefox, use Chrome or IE). You only have to use the other browser to log in and clear the cache.