I defeated grisletusk (and spent $5) and got my forest lord spell, but I got no pet. Don't you get a forest lord pet with the spell?
Evan level 58 life wizard
You must finish the main story line quests in Wintertusk and complete Nouilund Exposure, given by Grandma Raven - (spelling / grammar police excuse my errors) no fighting involved in the last area just, mend the bridge so you can cross, see the guy in front of the last brother you need the seal from and it's complete - go see your teacher for where the fight it for him. Watch those ice guys tho they go close to edges. Following main story line in Wintertusk actually goes rather quickly.
Just like prior school pet the spell and pet quests are different and you should be summoned by your teacher at appropriate time; if not go and check to see if quest is waiting for you. Also search update notes for Wintertusk an it should detail when and how of your school pet.
You must get to nordrilund to obtain the pet and talk to the guy Professor wu sends you to and that's the seperate quest that you need to complete and when you do your professor will give you the egg