Yep, you can at the least go thru some hassle, at the worse you can do jail time. As everyone says, low profile. The other thing you got to worry about is most employers have HR policies regarding weapons at work (I don't even tell people at work that I carry a 3" folding knife). Check your employee manual. If you work with this guy and he makes a claim that you brandished a weapon, not only will you get into possible legal trouble, you may get fired.
My advise, if possible avoid the guy, and don't carry when you know you will be around this guy for a few days. If everyone knows you carry, start the rumor that you don't carry anymore because of this. If you got a big CW, get something smaller and less noticable. When everything dies down, then you will be ok to start carrying again and this time do not tell anyone.