Missed heroin IV shot in neck.. almost a week later: Red soft lump, no pain.

[BoboBiggins]

I missed a shot of heroin in my neck last week. It bubbled up instantly when i missed, a little painful. Next day a lot more pain and a pretty decent size bump. Day after that pretty bad pain and the bump was a little more red. Almost a week later now all the pain has subsided, the bump doesn't seem to be getting any bigger or any smaller. The lump is now soft and red. https://photos.google.com/photo/AF1QipOYDOZ1KZauUg48OjFc_oav64paskzXWyIu13EO-Link to the image.
Any feedback would be much appreciated.

 

[herbavore]

I think I would go to get it checked out if it were me.