Can acne get better, worse, and than better again when using a product?

I started using Patricia Wexler's acne's starter kit, and it made my face look so much better within the first use. I was really excited to wake up to put it on again. I take pictures of my face to see the differences and I recently took a picture after about a week of using it and noticed my skin looked worse. Is it possible, or usual, for any acne product that works to get better than worse and then better again? I just don't want to waste my time or money if not. Any comments are appreciated, especially with personal testimony, thanks! <3