SOLVED. YA Dystopian, wall around city, toddler pees on command [s]

[Carolyn]

Okay, no joke, the most prominent memory I have of this book is the toddler being held in the air by some important guy in a robe. The guy turns to the mother and asks if the toddler has any talents. The mom blushes and says "wiss wiss" and the toddler straight up pees on the guy.
Other notable details, the city is surrounded by a thick wall (so pretty much every YA dystopian novel). The main character escapes for some important reason, and as he's traveling he's driven nearly to insanity by some mosquito - like entity that makes him want to claw his skin off... Thinking if only he could dig out the mosquito it would stop bothering him. Apparently he had enough self control though because some previous travelers had caught the same "bug" and actually scratched themselves to death.
Read it in the 2000's, never finished it. Any ideas help!

[Olivand]

This sounds familiar and if I read it, I read it at the same time as I read Slaves of the Mastery.

I distinctly remember that bug. I'll do some research and get back to you!

[Daphne]

No joke, I googled "wiss wiss" and got the first book in that trilogy, The Wind Singer. I bet that's it.

[Carolyn]

Oh my God that's it! The Wind Singer! I tried googling that too and came up empty - thank you so much!! I read it the same time as City of Ember and I thought I was confusing it. You rock!

[Carolyn]

Turns out Slaves of the Mastery is the sequel, too!