Birthmark since birth?

the day after my daughter was born I noticed this bruise looking thing kinda shaped like a puzzle piece on her leg right under her bum. I thought thats what it was a bruise but it wasn't. Its a little hairy too. I noticed that when she would get goose bumps that it would kinda lump up kinda looked like cottage cheese under her skin just in that spot....I took her to a dr. on base and of course they didn't know and said as long as she was eating and growing that she was prob fine. It doesn't hurt her she's active and healthy she just turned one and its still hairy but not as dark as it used to be its really really light almost skin colored the best way to describe the color is kinda like milky coffee color and maybe not even that dark....and it doesnt' wrinkle up when she's cold anymore. does anyone know if this is just a birthmark....it seems like its going away it hasn't grown in size and the color has faded almost completely
Birthmark since birth?
Hair on it? It is called a hairy nevus and it can be a serious problem though not usually. If your Dr. doesn't know this... get a new Dr. You don't let something like that go on undiagnosed 'just in case'. Since you say it is lighter... and especially with the lumps... it could also be a cafe au lait mark, which is a sign of many things benign, but also of a cyst forming disorder called neurofibromatosis. "The most common feature of Neurofibromatosis I are skin lesions called a cafe au lait spots. These are flat, smooth, medium to light brown irregularly shaped spots than can occur anywhere on the skin. Many people have one or two cafe au lait spots, and these are often called birth marks. If a child has six or more cafe au lait spots measuring at least half a centimeter (about a 1/4 of an inch), then he should be carefully followed to see if he develops any more signs of Neurofibromatosis I. "

new year lily