If you can't see your post, it probably hasn't been approved within its section by the moderators. Don't fret — go to Newest Nodes and chances are it'll be listed there. Others will see it as well, so sit back, relax, and enjoy PerlMonking.
If you want to see unapproved nodes as well as approved ones, go to your User Settings and turn on "Show Unapproved Nodes".
If you need to change something about your node, you can go to it and edit it, even after you have submitted it. Alternatively, you can reply to your own node. Whatever you do, don't re-submit the same content! Our system isn't so unstable that node submissions get dropped on the floor.