Not Likely. Unless he came on your hand, then maybe, but just touching like that in the shower, correct me if I'm wrong, but I don't think its likely.

It's pretty much impossible. The precum would have had to contain sperm (which some precum does), but past that, the sperm would have to survive the pelting water and the soap you used to wash your vagina, which is meant to kill germs and is a harsh environment for the sperm. Then, if they somehow magically managed to survive that they would have to swim past the outside of your vagina, find its way inside of you, make it to the egg, and be at the right time of the month.

I would not worry.