I know a little about heroin but the skin rash could be little more than a result of any substance abuse . They tend to drink a lot of energy drinks which have no nutrients in them . That combined with a diet of junk food can leave the skin in terrible condition . My son was using , amongst other things ketamine & coke . My brother is a recovering heroine user . He smoked it as he was afraid of needles !! Heroin users end up getting not getting a “high” . They take it , in the end, to just “feel normal ” !!! We are conditioned to think of heroin as the worst but maybe nowadays with so many different drugs available it is no worse or better . I would do food drops to my son regularly , often with him not even coming to the door . He would tell me to put it in the shed and he would pick it up later . I would continually make excuses for his behaviour . I think some of my blackest times were down to self pity , hard to admit that even to myself but “why my son ” who had such potential . And shame in admitting to friends what he had become . Misplaced pride ! Do try to stay strong and not allow him to dominate all of your waking hours , sleeping ones too no doubt . The more often you say no the less often he will ask . Life is always changing , have a little trust that eventually things will come right and if not, then you boy is travelling a path of his choosing . X