Give it a few days, pagespeed insights is slow to recognize changes to a site; they cache results because their actual processor is very resource-heavy.
Though usually if you need something like pagespeed in the first place, there's probably something wrong with how the site is built -- particularly since a lot of their "suggestions" are more about trying to sell you something than it is making the page actually faster; see how they LOVE to shove CDN's down your throat, and can use that as the basis to rank a 70k website built from 6 files lower than a 2 megabyte monstrousity built from hundreds of files.
First time I saw that type of result, I knew pagespeed had outlived it's usefulness...
Out of curiosity, how big is the actual page, how many separate files is it loading, and how scripting heavy is it? That's all you really need to know to gauge a site's quality and speed... you use a tool like the "web developer toolbar" for FF's "information -> document size", and most of the time if you know ANYTHING about building a website, that's all you need.