I doubt it has anything to do with the actual ligation, but there are plenty of other possibilities.
I'd go the hospital and request the operative report, including anesthesia report, for a list of the medications given. Also, what medications did you take afterward?
December was a long time ago. Maybe you are still taking something that's causing the hives.
You are already seeing an allergist. High WBC can mean infection. You probably need this checked again.
Keep a daily journal. Include all the meds you take, and even the foods and drinks you eat. It could be a coincidental food allergy.