What Causes Large Lumpy Hives With Pain At The IV Site?

3 weeks ago I went to emergency room for severe back pain. They gave me 2 doses of morphine thru an Iv in my hand. I got what appeared to be large hives near injection site. The vein where the needle was as well as where one of the hives were, are still very painful and lumpy. It looks like they are even getting worse. What could this be and should I be concerned?