At first sight this looks like he activated UV Borders in the uv editor, wish can sometimes have a very weird behavior. Have you tried to deactivate that for now ? I think it's toggle UV Border or UV Texture Border. You should be able to find it with the UV Editor marking menus or in the dropdown menus.
So i just fixed one problem for another to pop up. I haven't seen this before, i went to uv map one of my objects when all of my wire frame just went super chunky. Whats odd is it also affected my UV editor. But when i close maya and reopen it goes away, until i uv map then it comes back and wont go away. Any help would…