I Had Two Spots In My Arm That I Honestly

I had two spots in my arm that I honestly thought were spider bites. Almost 2 weeks later it turned into a rash and started spreading. A little swelling. A LOT of itching. So bad that it wakes me up. It moved to my other arm. A spot in my chest. And a small spot on my shin that started snaking up my leg. From a spot to about 4 inches. All seem to be near veins. More like right on top of veins.