The posts I read when I had the horrible sore in my mouth (I think I searched for "oregano oil" and "herpes" or something like that) said that oregano oil would force herpes up and out for good. I have never had cold sores on my mouth or genital herpes -- this one was on the bottom of my tongue and one doc treated it as a canker sore even though it was enormous, then I happened to go to my real doctor and told him about it, and he said, "I can't believe that people are still not calling canker sores 'herpes'." Apparently we are all born with dormant herpes -- there are 5 kinds, with oral and genital being just two.
I'm not familiar with olive leaf extract or CS, but I do know that a little oil of oregano goes a long way! I would not rule it out for down the road. And search the site for oil of oregano and herpes -- it is pretty interesting! I was prescribed famvir during that episode, but ended up not taking it, and I hadn't started using coconut oil. which is anti-viral.