Nit Boy Book by Tristan Bancks

Meet Lewis Snow. He has the worst case of nits in world history. His teachers and mum want to shave his head. But Lewis has had nits so long, he thinks of them as pets. The whole town is itching and they want to get rid of Lewis’s nits, whatever it takes.
Ned lives on Lewis’s head. He’s a little nit with a big destiny – the world’s first-ever jumping nit. His dad, the Head Louse, wants Ned to help nits take over the world. Trouble is, Ned’s a stay-at-home kind of guy. He likes it on Lewis’s head. He’s a vegan who hates the taste of human blood.
And you thought you had problems.