Arm pain/seroma/cording from removal of ONE lymph node??

A friend of mine had one swollen lymph node removed from her armpit a couple weeks ago.  She doesn't have cancer and isn't undergoing any treatments - i.e. it wasn't a sentinel node biopsy... she just had a swollen node removed.

Anyway, she now has a seroma, and is experiencing a sharp/shooting pain in her inner upper arm.  She describes it as nerve pain.  She also mentioned feeling something "like a cord."  Is it possible to get axillary web syndrome (is that what it's called?) from having ONE lymph node removed??

She doesn't want to have a check-up with the surgeon because she doesn't think anything can be done about this and the pain will go away on its own.  Is she at risk for lymphedema?  IS there something that can be done to reduce her pain?  I'm not sure where to look... every time I try and Google this stuff, I just get links about breast cancer patients having mulitple lymph nodes removed.  This was just ONE node.  And she doesn't have cancer.