picked up a blue tuxedo urchin today. Noticed these spots on the top of the urchin looks like bald spots?? Got it acclimated and it's moving around in the tank now.
It's damage, more than likely from it's long trek to reach you. Hopefully you have lots of food for him to munch on so he can repair. Also ensure you have stable alk, this will help in the reparation process.