what happened to Puck? he's coming back right?

He drove his mom's car through the front of a convenient store and stole an ATM xD

He's now in juvie and they're not entirely sure when he's getting out.

Mark may have breached his contract by releasing and promoting his own album and band. He is gone in ep 2x05 and will return the ep after. The ep is basically about him.

(source: article in link section)

yeah sure, it couldn't be as gr8 without him

Apparently when he DOES come back there's going to be an episode revolving around him.