Recently I've been experiencing a bug with the pen tool where when clicking to place anchors does not show neither the anchor nor line unless I'm clicking and dragging to add a curve, but even with that there's weird graphics to it. moving the canvas or zooming in or out reveals the anchors and lines but doing that after every anchor point isn't really intuitive.
The image I've attached has probably over 50 anchor points already placed. the ones you do see are once that I clicked and dragged to add curves.
What version of Photoshop are you using? Is you GPU detected and enabled in your Photoshop Preferences Performance section. Do you have path rubber band turned one. When there are many control points they can be so close to each other you can not tell what a control is doing unless you zoom way is to separate control points displayed.