Hello and welcome to HCM, I read your query and understood your concern. While iodine contrast media has been implicated in delayed side effects, photo sensitivity is very rare. since iodine containing other drugs have been reported to cause photosensitivity , chances cant be ruled out. So either it is that, or there was a problem with your tanning bed and you got a sunburn like reaction. I am more convinced towards burn. Take an oral anti inflammatory like ibuprofen and oral anti allergic like cetrizine or loratadine. Apply ice all over you body or take a cool bath, and while the skin is still damp, apply a soothing lotion like aloe vera or calamine. It ll bring down the redness and hives. Hope I helped