I'm adding a parallel comment rather than editing my existing comment because that adds one to the count and that sort of thing probably boosts engagement^tm^.
It may be too late for this now if you've significantly warped either of the pivot screws. But the trick for getting these headless screws undone on a balisong is to crank them with the knife latched. The idea is that the force going down the handles will bind the sides of the screw posts against their holes in the blade and/or the handle, holding the female end tightly enough that you can undo the male end. This works frequently enough that I'll classify it as "often."
You can perform a similar trick on a single pivoted knife, i.e. a normal one, by clamping it in two blocks of wood in a vise such that you're pressing down on the spine of the blade right over the pivot.







