Me, gf had foreplay, no penetration, rubbed penis on her external. No ejaculation. She's missing period and has spotting on second day. Pregnancy chance

See answer. All one can say is that pregnancy highly improbable from the circumstances you describe. No penetration and no ejaculation is not going to lead to a pregnancy. Recommend consider doing a pregnancy test on basis of the rest of your gf description regarding missed period and spotting.