I have a red mark with a white center that showed up the other day on my arm . It looked like a burn , with a worse burn in the middle, flaking skin. However, I think it has grown a little. It was very tender (like a burn would be) the first evening I noticed it. It hasn t hurt since. The white skin in the middle is flaking off in the shower. I can t say for sure it has grown, but it seems a little bigger. How long should I watch it, or should I watch for anything else before making an appointment to see a doctor?