It was 3 and a half weeks ago that I found out my girlfriend relapsed on heroin. She was an addict before I met her so I'm not sure what to look for. She told me she has not shot up since the 3 and a half weeks ago. I feel like her arms might be fresh though, but I can't tell if they are marks from 3 and a half weeks ago or if they are from recently. There is a pink line and I can see like 2 pink/red dots. How long do the dots last after shooting up? I feel like that might give it away if she's done it with or couple days or even today? Can someone more experienced with this let me know how long those dots should last or if they're are any other signs I should look for regarding track marks and how recent they are?