Is it possible to unsee things?

Yesterday I came across this video online of this guy being beheaded with a knife, they did it half way thru his neck and he was gagging, then he died and they finished cutting it off. It was extremely graphic and I think I may be scarred for life. THIS SORT OF THING SHOULDN'T BE ON THE INTERNET. But it was.. what can I do to get it out of my mind :(