Your intact (unbroken) skin on your hands is too thick for bacteria to penetrate. There is no risk from fingering.
What you felt was surely her cervix, and not a syphilis sore.
She used a condom for oral sex, right? She is using a condom to protect herself from her clients, not to protect you from her. She is trying to protect her body, her livelihood, her income, whatever is important to her. You view her as someone with all kinds of diseases - she views you the same way.
So you're fine. There's no risk here.