Well, he always has the advantage early on. You should never fight a teemo 1v1 till level 6 or so lol just let him harass you every now and then, and let him push to your turret (its going to happen whether he likes it or not).
By the time you are level 6, you should kill teemo easy no prob with wither + ignite + ult + Q. His blind doesnt last forever. --- LoL IGN: The Camel Rider