Arm bend very swelled and red after Heroin injection

[Justtoknow]

Hey all. I'm trying to figure out what could be wrong with my armom at the bend area. About 3 days ago I injected. I didn't get a rush but it also didn't Burn like I missed or burn like I hit a artery. My boyfriend did hit me in a different spot in that area then usual though. Right away it started to swell and it's been red and warm. And hurts..it's hard and not soft. Just trying to figure out what it could be and how to get swelling to go down. I can post picture if needed.

 

[keeping]

sounds either like a miss or an arterial shot..
keep an icepack on it and if it keeps gettng worse then its time for A&E