I'm assuming you're referring to a song or music piece. "Missax Young Dumb" seems to be related to a song by MissaX, a popular YouTube personality and musician. Lightroom Presets Japanese Style
The song you're likely thinking of is "Young Dumb" by MissaX. Unfortunately, I don't have information on the specific music composition or notation for this song. Video Title — Pure Lust Lena Reif Upd