If you think this is bad i have a scary story for you. One day in my beginnings of IV dope i took a shot one morning, and i clipped a nerve (i didn't know that this had happened at the time, i was high already) and pushed in my plunger to take my second dose of the day. After i was done drooling on myself (this dope was exceptionally better than my usual) i came out of the blur and realized, holy shit, i have hives going up and down my entire right arm... From hand to shoulder! then i tried pushing on em to see if it hurt.. MY WHOLE ARM WAS NUMB. So imagine my thoughts... i decided that id take some diphen and relax, see how things went. Things went well, numbness faded away and the hives left. No big deal. this is quite a common occurrence (the hives)