Could The Wound With Hanging Piece Of Skin Be Due To Meth Burn?

I guess I should ask you...my girlfriend has cheated before... but another lie of beers had haunted me she claimed she got a cistern burn that never healed until the day I discovered it when touching her leg bur there was still a piece of skin still clinging on the edge of her injury closes to her vagina. ..now I am her a year later & she still acts like it was a burn... but she now claims it was a meth burn. .. she was making a pipe for a friend & some spilt on her skin...but still if you ask me doesn't seem like there should have been a piece of skin still clinging on & still stretchable. ..I think she was having sex & maybe the guy was still wearing jeans or something. .. what do you think