Photoshop :: Polygonal Lasso Tool - Can't Intersect Original Selection Line?

I'm in the process of selecting the head and shoulders of a person and got about 2/3 rds of the way around which took me a long time when somehow the end of the line I was working shot across and made connection to the beginning point which ended my selection process. Maybe I clicked too fast or something but it happened and now I'm left with part of a head and shoulders selected.

I've tried working with the plus and minus to try eliminate the line that shot across but I'm not having any luck, maybe it can't be done.

When I try to add or subtract it won't let me intersect the original selection line, I mean I can use a place on the line to anchor my starting point butwhen i come back to the original selection line at some other point, it's not showing the the little circle indicator that tells me I've completed the selection.