How To Treat The Swollen And Painful Part In The Neck Caused By A Injection?

This may be a strange question, but strange or not I am very concerned about my friend. We both inject meth pretty much on a daily basis so we are both some . Generally not that big of a deal. But this what familiar with an occasional miss, but this is not like the others. I helped her inject the shot in her neck just under the left jaw bone and it seems that I may have hit directly in her lymph node. Almost right away her gland swelled up the same way my dose when I have a really bad cold. It has been almost 24 hours now and the swelling has not gone down at all, its actually gotten more swollen and is very painful. Any advice? Thank you