Came on the outside of her vagina, had sex 4x/24hrs, shes on the pill, can she get pregnant?

My girlfriend and I were messing around and had sex on friday night and I ended up pulling out at last second and busting on the outside of her vagina.>>  i know (well at least I think) she took her pill earlier that day so I think we are fine but then we had sex the next morning when we woke up when she hadnt taken her pill yet and i didnt see her take her pill afterwords eaither...<< that time I did not fully cum but i may have pre came inside of her (mind i say i dont think she took her pill).. we went to mcdonalds.. came back and surely enough we felt like going at it again.. once again I did not fully cum but there is a possiblity of pre cum and i dont think she had taken the pill still.... then later that day we went at it again while in the shower and yadayadayada *same story* anyway I'm wondering if she can get pregnant from the fact that we had sex 4 times in between the time that she took her pill?? Is the chance of pregancy greater? Please help, thanks!