Early 30s guy who got blackout drunk daily as well as doing as many uppers as I could, staying awake for days not eating, almost getting scurvy as a vegan, and otherwise doing everything you can to your body thars bad for it drawing the line only at needles for most of my late teens through my 20s, the longer term damage will start to be problems all at once and won't go away, they just won't get worse if you smarten up. There's no healing some stuff, there's just not making it exponentially worse. Parts of me don't work quite as well as other people now and I'm just kinda stuck that way now. So yeah, don't fuck around kids.