Does Karate like Shotokan have a high guard like a Boxers? How would they block a punch to the head?

Sensei Scandal is right. Styles like Shotokan or Kyokushin use parries, the "blocks" that are used are both used to defend and to attack and create an opening. It's not meant to just stop the attack, it's meant to set up for a counterattack as well. The position of the hands is typically front hand (that of the front foot as well) forward and up around the shoulder, the other will be somewhat lower but vertical to protect both the soft abdomen and the jaw for attacks on that side. That's why karate punches are so much different than boxers' because it's less of a jab.