help with pathing

[Sakuria]

i had completed the terraining of my map and i had decided to save some time with pathing blockers that i would just turn the collision of the trees i used back on. Of course i used a custom tree model and me being new to the editor (this is my first map) i saw a .blp under imported with the same name as the tree model i used.
Well now my map's pathing has changed to completely white, even when i undo this change (unwalkable, unbuildable and unflyable). So i have pretty much ruined my map and cannot think of anyway to rectify the problem,
thank you for any help in advance.