My daughter has about 4 small birthmarks in different areas on her body. This last March my in-laws had her in Orlando for the night when they noticed a small red mark on her birthmark on the back of her head. They said it was hard under the skin, then blistered up with yellow fluid and popped. I thought maybe it was just a bug bite that happened to bite her there. But since then she has had 2 more episodes exactly the same way in the exact same spot. Also her birthmark on her shoulder has on 3 separate occasions has done the same thing, had a hard knot under it and looked like it was going to blister but never fully developed. Please help me. I have taken her to the doctor the only one in our county and he said to wait until her head blisters again and take a sample. He believes there's nothing to worry about and just pushes it to the side. What should I do. I am very concerned.

Thank you,
Very Upset Mommy