crack was probably the worst for me:
psychosis wasn't fun
my psoriasis deteriorated into open sores all over my body
hair was like straw, matted all the time
bodyweight fell to seriously low bmi- i'm bingeing supersize vs superskinny and i was lower than all the superskinnies, and am quite tall too
couldn't physically eat a meal because my body was so unused to eating
destroyed teeth, £1000s of dental surgrery needed to fix
my skin way grey
i needed 6 lots of antibiotics in one year cos my immune system was just fucked
those are just what i know about, but the damage to my heart and lungs is probably worse than the relatively superficial/reversible stuff mentioned above
somehow drinking 100s of units of alcohol per week for at least a year, plus benzos for 6 years, didn't destroy my liver, for which i was thankful