Im so embared....what do i do?

so i was kissing this guy (not my boyfriend but potential) and like a couple seconds later his throat gets all itchy and his lips get swollen....apparently hes allergic to walnuts....i ate walnuts before meeting him....im so embared?!? he hasnt texted or called since....he probably thinks i have backwash now ;(...what do i do?!?!?!