Re: could i get preg if...
Precum does not contain seminal cells. However, residual semen can theoretical leak out of his urethra onto your hand.
But the chances of this happening is so low, I wouldn't bother worrying. Might as well wash your hands, though. There's no harm, and it will help rid you of some of the anxiety.
"I don't believe in magic. But I do believe in interpreting coincidence exactly the way you want to." -Sherman Alexie