Started Having Pain In Both Legs Between Heel And Knees.

Started having pain in both legs between heel and knees. Started out with about 4" turning red and breaking out with bumps or blisters. Above that area my legs began to swell badly. The tendon that runs behind my heels felt so tight I sometimes thought that if they just ripped I'd feel better. I either itch like mad, or sting and at times there is a deep dull ache around the top of my feet and up the ankle. My GP wants to send me to a dermatologist for the rash, but seems to want to overlook the tendon pain and swelling. Any ideas what this may be and what kind of doctor I need to see?