Can a girl get pregnant if the sperm didn't touch the vagina but it was on her skin?

I am assuming your partner "pulled out" just before ejaculating. If that is so, then there is a small possibility of getting pregnant as there are some sperm in a man's pre-ejaculate discharge. If there was no penetration prior to your partners orgasm and they just ejaculated on your skin then there is no chance of getting pregnant unless you (or he) touched the ejaculate and then subsequently touched your vagina. Then, as before, there is a small chance of becoming pregnant. Hope this helps.