How to close a surface after a surface trim?

Hello, I am making a surface model and have been left with a fairly complex hole after a sweep-surface trim. I can select all the edges that would close the hole, but can't seem to figure out which feature will make it happen. Boundry blend in blanked out no matter what I do or select, and I'm wondering if this might be it? Also, is there a way to "heal" these surfaces as the cut goes thru so later I don't have to close them? Thanks, Matt