"And little j's a fuckin' mess, but when he's offered just says yes" - Again this is a reference to Jasons wreckless attitude, he just cant refuse the drugs even though he know they are destroying him.

"So little j's a fucked up boy, who dulled the pain but killed the joy" - Heroin is a pain killer, but also a downer in a more ways then one .

"The tracks of time, those tracks of mine, little johnny's occupied" - Tracks marks are a reference to the marks on a herion addicts arms, as they shoot up at a higher part of their arm each time.

"Little Johnny's sad and fucked - First he jumped and then he looked". This is about being reckless - and how Jason's reckless attitude got him into drugs.