im suspicious that a close friend has been slamming crystal meth recently , ive noticed some tell tale behaivor, not eating, how usually hes extremly neat n now hes slacking , not sleeping enough, and also track marks around his ankles. he supposedly quit using about a month ago, but some of the marks on his ankles are still pretty red, like how the skin looks after a scab has healed but its still shiny and red? how can i tell the diffrence between fresh marks and old ones?