If you want to see who has viewed your collection on Facebook, there are a few different ways to do this.
One way is to go to your profile page and click on the More tab. From there, select Photos and then Albums. Find the album that contains your collection, and then click on the number of views in the lower right-hand corner. This will bring up a list of people who have viewed that particular album.
Another way to see who has viewed your collection is by going to the Activity Log page on Facebook. To get there, click on the down arrow in the upper right-hand corner of your profile page and select Activity Log. Once you're on the Activity Log page, find the section labeled Photos and look for an entry that says something like [Your Name] added [Number] new photos to an album. Clicking on that entry will take you to the album in question, where you can again see how many people have viewed it.
So those are two ways that you can find out who has been looking at your collections on Facebook!