Sunburn On Thigh And Knee, Burning And Painful. Skin Changing To Yellowish Purplish Color. Sign Of Healing?

Hi, I got a severe sunburn almost a week ago from today on my thigh and knee area and still have bad symptoms even now. It was burning and painful for the first 2-3 days and I had trouble sleeping at night. I then developed a couple yellowish blisters. During the first 3-4 days my skin was tough, hard to the touch and it was uncomfortable to fully straighten my leg and to walk. My knees swelled up too. Now, I am noticing more yellowing of the skin, although not blisters, but yellow skin and some purplish colored skin. The sensitivity is not nearly as bad as it was a couple days ago. Should I talk to my doctor about the yellowing and purplish skin?..or is that a sign of healing??