What should I do if I pissed off some road rage person?

I was driving down a street and I saw some person pull out fast of a parking lot and get into the middle lane creeping to get over. Once I passed in my vehicle they almost instantly got over and started to tailgate me until we got to the next light. Then they went around me because obviously I was driving way to slow and I gave them the bird not thinking much about it, assuming they knew how much of a jerk they were driving like. They did not take to lightly to this and got up right next to my car and rolled down their window and started yelling at me "why'd you flip me off man, blah, blah, blah." Then they pulled up to the other side where my partner was and started yelling at them. The light turned green and I pulled into the parking lot of our destination. We went in and got our stuff and on our way back the person had followed us in the parking lot and drove up all fast yelling again and threatening us when go out at night saying it was there hood we were in now. Now I know I shouldn't have flipped the bird and just let it be, but now I'm kind of afraid I'll run into this jerk again and don't want anything to happen to me or my partner. Is there anything I should do or should I just try and forget about it?