What Causes Itching Of Birthmark On Neck?

Hello. I have a birth mark on my neck, where my hairline is. It's either a salmon type or the strawberry one. It has been itching/ buring now for months. I tried dandruff shampoo, thinking that was the issue, but It didn't help one bit. I am going to the doctors today to get it checked out, what should I expect to find out?