What is this needle mark on her inner arm? [Platonic Downer Lyric Doujin]

[Murakumo]

In the original doujin "プラトニックダウナーリリック～ダウナー系元カノと×××する本～" (Betty), the girl Izumi has two needle marks on her inner arm, what does it mean? Is she a drug user or is it implied to be medical treatment? She is also shown with a bruise-like mark on her arm in a previous page and also says this is the last time she can see him

 

[greenlittleman]

It could be a needle mark, or, more likely, it could be just the way her elbow pit is drawn. Remove those lines and the arm would just look strange.

 

[Murakumo]

It could be a needle mark, or, more likely, it could be just the way her elbow pit is drawn. Remove those lines and the arm would just look strange.

the doujin explicitly states its needle marks