When you start to inject in your neck

Hello All, I have a question, why do addicts start to shoot up in their neck? Also, what does it mean when they have shot up in the neck and now they have a large bump on the neck? It is all bruised pretty bad....Can anyone tell me this? Thanks

[Life360]

Hi and welcome. My experience with things about this is that the veins in the arms collapse and choose the neck as an option.
Ive had blood test needles in my arm and when it was not done properly about a 3 inch circle turned blue and very bruised, could be the same with the neck as the needle went through the vein, into the surrounding tissue.
If you know the person doing this and you care for them you should try to get them help as seems they have lost all respect for their body which is not a good sign.