Hair on a birth mark??

Tayste

My 3 year old has dark black hairs growing out of the birthmark on his back?? And only the birth mark. There’s only a couple of hairs. I’m pretty sure this is recent, I can’t say exactly how recent though.

I have the same birth mark on my back but I don’t think hair grows out of it any differently than the rest of my skin ?? Is this concerning? I’m so confused. I called his doctor and left a message.