How should I react in a situation when a boy standing near me found out that my jean's zip is opened?

Question :- 

I am a girl. A classmate ( who is of very cheap mentality) was standing besides me and talking on the phone.on finding out that my zip of the pant is opened I immediately covered it with the top but after cutting the call he asked if my zip  defective.I know, now he will make fun of me in his group.

Answer :-

I know its a bit awkward situation for a girl but still,....Come on ,...CHILL,.. It was just a Zip,... though he make a fun of u(which I don't think so he does if he is a real gentleman) for how many days?!!!!,.. as the days passes, will also fades,..Be have a patience and never react to their taunt.
I have roamed all around the damn city twice or thrice with open Zip(without my knowledge) ,... Can't help,.. it just happens.. with me,.. with u,. with everyone,.. JUST FORGET IT.