At first I thought maybe it was phlebitis, so I had to look it up. I found an article that describe 2 instances of hardening aound the IV site. I put in the link. In case it doesn't work, briefly:
1. Thrombophlebitis: The IV cannula may irritate the vein triggering it's clotting mechanism. Hardening where a clot has formed. Recommended: Anti-inflamatories like Ibuprofin or Tylenol. (probably what your doctor thinks she has. Ask!)
2. Infiltration: the catheter enters surrounding tissue so fluids form a lump. They pull the IV and do it again.
Years ago, I remember having extreme pain from the IV, actually sitting and crying from the pain and the doctor had no sympathy at all. Heat compresses did nothing for the pain. A friend who was a nurse told me to try ice and that helped more than the heat (even though theoretically it constricts vessels). She also told me to have them put the medicine in a very large bag diluting the medicine so it didn't burn my veins. This doesn't sound like your daughter's problem.
Why didn't she get a PICC? Being stuck every 3 days is so painful.
I would definetely call the doctor. There is no reason why someone should have to stay in agony.
<a target=_blank class=ftalternatingbarlinklarge href="http://www.netwellness.org/health topics/ansthesology/ivcomplications.cfm">Text</a>