Why would you think it would hurt you? No one is going to tell you during interviews, "Well, you already got one professional medical degree, so you can't have another one, see you later."
The vast majority of cytotechs did not get a cytotech degree so that they could then go to medical school. They did it so they could be cytotechs. Like anyone who has pursued one professional field and then wants to go into another, you will get questions as to why you are changing fields, what isn't good about the one you are in, etc etc. Those are real questions which you need to have answers for. If you have the answers, great.