Perrié is a fascinating word because it's a colloquial past tense form of "perrear," which literally means "to dog" but is commonly used in Latin American slang to mean "to dance perreo" (a reggaeton dance style) or, in a broader sense, "to party hard."
However, in the context of this song, "Vieran como la perrié" (You should see how I perrié), it takes on a different, more profound meaning. It's used to convey a sense of struggle, hardship, and having to fight to get by, almost like "I really had to hustle" or "I went through a lot of tough times." This double meaning makes it a very interesting and culturally rich word to learn.
Adriel Favela is keeping a ledger. The song counts two groups of people from the years before anything worked out: the ones who looked away, and the handful who got in the boat anyway. The title line is the test he applies to both — "Cuando los necesité" [when I needed them] — and the verse around it is specific about what being broke actually looked like, down to not having the price of "una tortilla con sal" [a tortilla with salt].
What keeps it from turning bitter is where he points the gratitude. He thanks the doubters too, because their doubt is what he measured himself against, and he warns them that "hasta las torres altas a veces suelen caer" [even the tall towers sometimes fall] — success is a loan, not a deed. The chorus lands on the same idea from the other side: "al final de cuentas la vida es prestada" [at the end of the day, life is borrowed]. He offers his hand to whoever has earned it and tells everyone else to step aside, and the arrangement — banda horns under a singer who never raises his voice — makes that sound less like a boast than like a man reading a list he has had a long time to check.