Lyric discussion by Jules9 

I don't think this is to be taken on a literal level. I think it's a metaphor for when he was in the hospital (his breakdowns and such) that he lost his music and when he found it (or it found him) it was what saved him. Check it:

“oh, don’t you remember me? is your mind that worn? (Right there, if this were a girl why would she ask Max if he remembers her? He says earlier he doesn't know the 'girl')

we both were born to be one with that which the public scorned (Emo, hence the 'genre', is looked down upon by the general public)

though you were forlorn in despair with your drugs and your hardcore porn (He was so into drugs and jacking it he lost his artistic drive)

trust me, those days won’t be mourned. so lay your head on me.” (Those days are behind us, don't worry, put your faith in me.)

I also have a different interpretation for the last line, that he could use his past experiences for songs, see the "won't be mourned". They won't be, because Max used them for inspiration.

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