I made the mistake of leaving a headsail on a roller furling for winter wet storage.
I procrastinated, hoping for a couple more winter sails. When that never happened due early snow and freezing conditions I tried to wait for thaw to get the sail off. That never happened and then I left for Asia for six weeks.
By the time I came back from Asia and could get the sail unfurled it was BLACK with mold. Ruined.
Get it off if you can.