Pete,

Negative, you don't have to open up the gap between the door and the fuselage, they should seal perfectly. The reason that the door would not open is because at elast one of the hinges is preloading the door skin. When you glue the hinges, you glue them to the fuselage first, then you glue them to the doors with a thick bead of epoxy and you let them seat naturally where they want to seat on the door. You cannot force contact.

Too bad you cut the skin already, that was an easy fix!