should we be concernd of pregnancy?!

So me and my gf were fooling around two nights ago and my penis touched the outside of her vagina for about 4 seconds..it touched near the top of the vagina, i had ejaculated about an hour before but im pretty certain all the sperm had been wiped up or had dried, this was a day after her period ended and i did not penetrate her...do we have something to worry about or are we paranoid?? please help:( also she took the plan b one step pill to be extra safe...so we should be okay right?