Missing Festive Maokai Skin

Oh Riot Gods,

I have returned from a long hiatus from League of Legends, only to discover that when doing an inventory of my champions and their skins, my Festive Maokai skin is no longer showing up as owned in my inventory. I distinctly remember owning this skin, as I frequently made jokes and yelled "PRESENTS" whenever I threw saplings at devilish foes.

Unfortunately, due to my long hiatus, my account purchase history does not go back that far. Is there any among the Riot Gods that can look into my missing Maokai skin for resolution?