Turista literally means "tourist". It's a common word, but Bad Bunny uses it here in a deeply metaphorical and emotional way.
He sings, "En mi vida fuiste turista" (In my life you were a tourist), to describe a lover who only experienced the beautiful, surface-level parts of his life, like a visitor on vacation. They never saw his hidden pain or "heridas" (wounds), making this a powerful metaphor for a shallow relationship.
This song is all about a temporary romance, and Bad Bunny uses a perfect metaphor for it: a tourist. He tells the other person, "En mi vida fuiste turista" (In my life, you were a tourist), meaning they were just passing through. They only saw the good stuff, the highlights reel of his life, like a beautiful sunset or a fun dance. He admits, "Tú sólo viste lo mejor de mí / Y no lo que yo sufría" (You only saw the best of me / And not what I was suffering).
He's not bitter about it, though. He even says it wasn't their job to fix his old wounds. Instead, he explains that he's been hiding his feelings for a long time because "Tengo miedo que me hagan más daño" (I'm scared they'll hurt me more). The song has this relaxed, accepting feel. He's basically saying, if something more happens between us, great. If not, that's okay too. For now, let's just enjoy the moment because the night is beautiful, but as he sweetly adds, "Pero no tanto como tú" (But not as much as you).