Hmmm, I think the way your skin reacts to tea tree oil depends on the person...I use it straight 100% w/o problems, never dries my skin or burns it, just a nice tingle feeling, maybe I am just not sensitive to it...if I ever have a pimple I dowse it in straight tea tree oil and by next day its reduced to almost nothing. I am even able to apply it to my whole face and after it absorbs my skin has a nice healthy glow to it (when I do I put it all over my face, once a week, I apply a cream containing vitamin E after the tea tree oil has absorbed).
If you are not sensitive to tea tree oil it is an amazing skin cleanser.
That and the raw egg masks are the only two topical treatments I ever found to work on my own skin type, I tried witch hazel and many other things and they had no effects on me whatsoever

Obviously one should try a little first to see how they react to it, I heard that tea tree oil cause some people to have red spots where the acne was, for me it causes any spots to clear up completely, how weird, everyone has their own sensitivities especially when it comes to skin