Tetracycline only affects your teeth as the adult teeth are growing in, when you're a child. I was sick a lot as a kid and took a lot of it, and mine got yellowish along the tops of the top teeth and bottoms of the bottom teeth. Since the discoloration is at the core of the teeth, not a surface stain, the only cure is porcelain veneers, which I have 8 of on the top. Some people get grayish colored stains from tetracycline as well. But it won't affect you once you have all your adult teeth, which is usually when acne kicks in, so don't worry about it!