Does he think I'm a prude now?

Sooo ther's this guy at my work and we were joking around about his d*** and he asked if I wanted to see it and I said sure and then he goes "show me your t*ts" and I said no cause I was on my period (and in case you don't know they get like sore, swollen etc) and he acted like that was a lame excuse (he asked twice this week and both times my response has been the same) The first time though I kinda felt my face get red (idk if he noticed or not...it may have just been me) But now I'm afraid he thinks I'm prude but I'm not and I totally want to ha ha so do you think he thinks I'm prude and if so what should I do? lol