Viewing your account [i]via the app[/i] I can see [b]Dark Fluorescence[/b] listed in your Collections under the Seasons category. When viewing [i]my own[/i] Collections tab in game, [b]Dark Fluorescence[/b] appears on the first page of the Seasons Shaders list in the third column fourth from the top; I would presume you will see it in your Collections in game in the same spot. As for finding it in your [b]Appearance Customization[/b] menu or when swapping Shaders on your weapons, bear in mind that the order in which Shaders are listed in these menus is not always organized in a predictable manner, with Shaders tied to a specific Seasonal Event sometimes being grouped by year yet spread across different pages. Speaking for myself I find [b]Dark Fluorescence[/b] listed on the bottom half of the tenth out of fifteen pages (although this will undoubtedly be different for you based on how many total Shaders you have unlocked and how many you currently have Favorited). If it helps you to locate it, the Shader appears in my Appearance Customization menu flanked on the left by [b]Gambit Duds[/b] and [b]Vanguard Unyielding[/b] (both of which have [b]Black Armory[/b] icons) and on the right by [b]Shadowstrike[/b] and [b]Amaranth Atrocity[/b] (with [b]FotL[/b] icons). Look for a Shader with a burnt orange upper quadrant, dark brown left quadrant and an inner diamond with two shades of grey. (΄◉◞౪◟◉｀)