Well, I don't know if "paradox" is the correct rhetorical term here; I think perhaps this is an oxymoron. " I don't think it's really a metaphor, since the song is not being compared to an actual thing. "He stabbed me with the stiletto of his song" would be a metaphor, for example (and alliterative besides).
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And by the way, I first heard this song sung by The Carpenters, oh so very long ago. Never heard of the Fugees