Exiting the X-MEN: INVASIVE SPECIES EVENT QUEST has removed it from my game.

SpideyCA

I was playing the X-MEN: INVASIVE SPECIES EVENT QUEST and chose to "end quest" to exit a level where I was overmatched and now the entire quest is gone from game play! What happened, I could previously do this as I play the harder levels first and then play the easier levels. Can I get it back? My user name is SPIDEYCA.