Allergic to Weed? I had small bumps on my left hand

First here is some background info I went to a concert yesterday and people were smoking weed. I have a heart problem (Had no left Ventcicle and my system was flipped). I am almost 13. So I woke up this morning and I had small bumps all over my left hand and it's really itchy. I also have this on the right side of my neck near my collar bone. I've never had this before. Am I allergic to weed smoke? I tried not to breath it in and covered my nose. I don't know what to do...