Before posting this, I searched GOG forum and Steam and found nobody asking about this.

This is my first time playing and I'm having fun. When I created my character, I picked the guy with the pentagram in his head since he looks like a magic user and I love playing mages.

I just loaded my save after talking to the King to deliver the cave-in message to Pog, and now my head model is completely different. I have red eyes now too, and I'm pretty sure this head model wasn't even an option on the character screen.

Is my guy cursed or something? I swear I haven't been evil or anything.

Photo attached, and imgur link here: https://i.imgur.com/6udpgIR.png

You probably accidentally activated the change player skin cheat. It will cycle through the available skins, including one that is used in the make special hero and MAX cheats as well as one additional appearance that can only be found in this way.

Just cast the change player skin cheat (enter casting mode, hold mouse button and move the cursor up down up down up down) until you get back to the skin you want.