Desvelo comes from the verb desvelarse, which means to stay awake or to lose sleep. It's a more poetic and intense way to express sleeplessness than simply saying "no puedo dormir."
In the song, Alemán sings, "Mi amor pensando en ti siempre me desvelo" (My love, thinking of you always keeps me awake). He uses this word to convey the depth of his feelings, implying that his thoughts of his beloved are so consuming that they prevent him from sleeping. It's a beautiful way to express profound affection and longing.
In "Crema," Mexican rapper Alemán paints a picture of a life split in two. On one hand, he describes a world of success and luxury: getting off a plane to a VIP welcome, traveling with four full suitcases, and having enough outfits for any time of day or weather. He turns his pain into profit, boasting about sold-out concerts and hit songs. The phrase "la crema" itself means "the cream" or "the best," highlighting his top-tier status.
But beneath the surface of success, there's a struggle with a past relationship. Alemán admits his fear of an ex-lover getting back into his head, remembering how he used to drop everything for her. He sings about breaking those chains and turning his sorrows into money, but he also reveals that this person still occupies his thoughts. He finds temporary relief in his financial success ("contando los ceros" or "counting the zeros"), but he's searching for a different kind of reward beyond just money.