I Have An Area On My Upper Arm Where I'm

I have an area on my upper arm where I'm experiencing moderate to severe itching, accompanied by two areas the size of a soda can lid where the skin feels thicker and stiffer than the surrounding areas. This started about a month ago and looked almost like insect bites and has since changed into what i described above. there is no visible discoloration on the surface of the skin except reddening from scratching. Along with thickening and stiffness of the skin it also feels bumpy. I have not tried any OTC anti-itch creams or medications.