Can you get pregnant if sperm doesn't go inside you but is just on not in the women?

It's not advised to ejaculate anywhere near a woman's vagina in case the sperm does manage get to her opening. Once sperm is within the woman's libia (the flaps near her main opening) it's a vacuum action up into her uterus area where she can fall pregnant. It's very unlikely that the sperm in your question did impregnant the woman's egg; but if your going to use the pull out method** as a form of contraception then it's advised that the sperm goes somewhere where it cannot come into contact with the woman's legs or vagina (eg: a tissue, towel, on the floor)

** pull out method is when the man pulls his erecation out of a woman and finishes off outside her vagina.