Sadly, I don't think you can find the song again easily, if you had it on mobile. However, if you remember the melody (you may not if you don't know which one you deleted) you could try singing it to one of those services like SoundHound (like Shazam). If you ever listened to the playlist on a computer somewhat recently, you could try going to the queue, and then clicking "history" somewhere on that page, and search through that.
I hope you find the song, it's always a bummer when good songs go missing accidentally. I'm always doing that on my Mac,
jeeprace98