The short answer is no, there is not a very high chance of pregnancy if sperm touches the outside of the vagina. But why are you putting yourself at risk!? Since you are obviously concerned about getting pregnant, why do you think it's a good idea to be messing around with genital to genital contact WITHOUT a condom? The guy may not have been inside you this time, but guaranteed if you continue making out in this way, you will very likely get into a situation where you'll feel pressured to go all the way. When that happens, not only will you put yourself at a high risk for an unwanted pregnancy, you will also put yourself at risk for sexually transmitted diseases.

My best advice: You need to do a much better job of educating yourself about the risks of being sexually active.  Otherwise, one thing is gonna lead to another and you're going to find yourself pregnant.