When we say skin to skin contact for infections like syphilis, herpes and HPV, we mean genital skin to genital skin, not skin like your back, butt, legs, etc. If your genital area never came into contact with her genital area, you're fine.
Someone with any of these is only infectious from the site of infection. If they have genital syphilis, they are only infectious from their genitals. If they have an oral syphilis sore, they are only infectious from their mouth.
You have no risk here.