I had the halo pap. there was nothing in the cup but my left nipple had some yellow discharge, hurt for hours, & was itchy. is this normal?

I believe so: I do not use the halo in my office. From what I have seen in how it is applied and used, the symptoms you describe make sense and are related to the procedure. Unfortunately, we do not know what to do with the information it gathers, which is way it is not widely used. I'm sure ther are many of my colleagues who may use it and have other responses and i look forward to seeing their answers.