I bought mine from www.lifelinewater.com When you go to the website they will give an explanation.
I did one spot in my neck and that is gone, it was light and dark and may be pre-cancereous. It had gotten bigger.
I have been doing several spots on my legs. So far I can't tell you yet, because I had to put a second layer on.
Now I am doing three spots on my face, but you might not want to do it. It becomes a firey red spot, sometimes swells and gets a crust on it. Not attractive. I don't really leave the house so I could try it. I started this 5 days ago. It is not a quick fix.
I think bevpirt is doing it too. May be I read it at Andreas' forum. I have to recheck.
So I would say certainly worth trying. Go to Google and may be you can find more websites.