Some users have come across the issue of not being able to manage their lenses in the app (located in the carousel).
Solution:
To see all the downloaded lenses in the app, you need to navigate to Manage Lenses. By grabbing the three-bars icon you are able to drag and reposition the lenses in the order you want them to appear. When in the Manage Lenses section, if you swipe left on a given lens, you’ll be given the option to remove it completely by pressing delete.