Are my hives being caused by using Oxycodone prescribed after my Breast Augmentation?

I have chronic hives as a result of SLE Lupus. I had my BR surgery two weeks ago and have had a terrible hives flare up. I have asked my surgeon wether it is the Oxycodone use or the surgery that caused the flare up and he was not sure. I am still taking half a tablet at night for pain so I can sleep. I also take benadryl, zyrtec, allegra, and hydroxyzine. Have any of you seen this before? Also, is it okay to begin a course of Prednisone since I am two weeks post op?