Is this skin cancer on the scalp? (Photo)

I went to get highlights a while back and my head was chemically burned by bleach after sitting at the hair dryer for a while. Most of it went away after a month, I never went to the doctor. One part of it never went away and it has been two years now. I went to see a skin doctor and he said to inject it with kertisone to reduce the size but he didn't recommend or talk to me about what it was. Any clue?