OP, I think you should elaborate more on what your professor said. What did he say he will do? In general, a lot of these cases will be handed over to Judicial Affairs and first-time offenders are given a warning rather than a punitive disciplinary action. That is usually reserved for repeat offenders and bigger academic criminals, so to speak. FYI, the way how judicial affairs works is analogous to a legal process of prosecution and defense where you will get a fair chance to explain yourself in a hearing and even appeal the decision should you disagree with it. But I highly doubt you'll have to do so since the weight of your wrongdoing is relatively light.