Here's How To Change How Many Friends Show In Your Facebook Friends List
Changing the number of friends that display in your friends box is easy, just follow these steps:
Go to your profile page, (not your "home" page where you see your news feed, but your actual profile)
Look down to the lower left-hand side at your Friends list
Click the little "Pencil" icon on the Friends box
Where it shows the drop-down arrow saying "Show X friends", select how many friends will actually show in your friends list. Unfortunately you can only choose between 6, 9 and 12 friends.
When you're all done selecting how many friends you want to show, just click outside of the friends' box somewhere, like a white spot on your profile page
For a visual reference, check out the screenshot below