Swollen lymph node in neck & on hand should I panic?

Has anyone experienced pain in the hand or swollen lymph in the neck? I've been having pain for about two weeks. I can make a fist, but cannot flex my hand. There is a small lump on the top of my hand near my wrist. About a week ago I noticed a lump on the side of my neck that seems to swell and then it goes down. I went to see my Onc last week and she gave me an antibiotic, Cephalexin, but after 5 days there is no change. I go in for Herceptin on Friday and may be able to speak with the doc, but I'm super nervous and just wondering if anyone has experienced something similar.