Bruises on Arms = Heroin Addict

Before I knew my daughter was a heroin addict I just thought she was a high strung, rebellious teenager going through what most teenagers go through. I had no idea that she was a heroin addict. I noticed that her personal hygiene habits and clothing styles changed. I also noticed that she was having trouble controlling her anger. She was happy then she was sad. It was a roller coaster. She wore a white, long sleeved t-shirt almost everyday and rarely took showers. One day she was rubbing her arm and her sleeve rode up on her arm and I noticed lots of bruises all over her arm. I asked her about it and she quickly said, "[so and so] has been playing around and grabbing my arms." I said, "let me see those bruises" and I reached over to pull back her sleeve and she jumped up and said, "oh, I gotta go, I'm late." I said, "you tell [so and so] not to put anymore bruises on your arms." God, I was so naive. Because of the bruises, I thought she might have a disease. So, I did a google search on "bruised arms" "arms bruise easily", etc. There was not one result that came up during my searches that implied anything about bruises and heroin addiction. I guess bruises on the arms and heroin addiction is such a [no brainer]...that its just not mentioned.