Could I get charges for asking a costumer to fix difference out side?

I'm a delivery guy for a pizzeria, and yesterday where at a store in line to pay but I forgot I needed soap so I told the guy I was coming right back and I did but he dint like it and he told me it was not fair for the other costumer but I dint do anything wrong, I came back before his turn. I know I could be nice but I was not, I course and ask him to fix it out side not in the store. I was not going to fight him because I have surgery in my neck so a punch can get me paralyze, I kind of waited for him but also walking to my car, I know I behave totally immature and stupid, I finally got in my car and drove away not before I call him a "B" the bad part it was that I had my pizzeria uniform so he can probably find out where I work. what can be the worst? I mean the guy was smiling in sarcasm like I"LL GET YOU FOR THIS". what can be the worst that can happen to me?