Without knowing what STD your partner had, it's impossible to answer this question.
I agree with Life360 - you should get tested. While cunnilingus is lower risk than vaginal, you still have a risk for syphilis and gonorrhea. Even with protected sex, you have a risk for syphilis, HPV and herpes.
I forget to mention that my cunnilingus to her is not protected and she also did protected fellatio to me.