Desquitamos comes from the verb desquitar, which can mean to get revenge, get even, or make up for something. It's a strong and somewhat dramatic word that isn't heard in every pop song.
In the context of "Mándame Una Foto," the singer uses it to express a longing for physical intimacy. He sings, "Las ganas que tenga más me las guardamos y cuando esto se acabe solito nos desquitamos," implying that they are holding back their desires now, but once the distance is over, they will "make up for" all the lost time and affection. It adds a layer of passionate anticipation to the lyrics.
Ever missed someone so much it feels like you're going crazy? That's the heart of 3AM's song, "Mándame Una Foto." The singer is struggling with the pain of being separated from someone they love deeply. He describes feeling lost, lonely, and unable to bear the "weight of this loneliness." The distance is so difficult that he feels like he's "going crazy" and that the "lack of you is going to kill me."
To cope, he clings to memories and digital connections. He asks his love to "send me a photo" just to feel like things are still the same and to get a "signal that this distance will never affect us." He finds comfort in seeing her on his phone, even though it's hard to accept she isn't physically there. The song captures that intense feeling of longing in a long-distance relationship, where every moment apart feels like an eternity and all you want is a sign that your love will survive.