X you always make me laugh with what you say. Love the lint brush. I also have had this happen with all of my kids. Although it was very early on. about 2months .
My dd9months is just growing hers back in, it's almost all there now. But it is sooooooooooooo normal.

Keep it clean and when they stop sleeping in the exact same position it will start to grow back.
I heard an old wives tale that if you take a magnet(like the fridge magnet) that it helps. I only did this with out Newfoundland dog after he had surgery and was bald and it helped with that (it was a bigger magnet though). But i never did it for the kids.