So I presume if I want a specific ending to a piece of fate locked content that requires a mask of rose I will need to wait til next valentines day to complete this story?
No, you should be able to buy a mask of the rose from the bazaar. They’re pretty cheap too, so as long as you’re in a place with bazaar access you should be able to buy one.
Romulus is right; Maxwell’s Hattery sells them.