Sounds very much like my youngest's H - except his is dead center on his forehead, down from the hairline! At 17 months, we started to see signs of involution - some gray patches. Now, at 22 months, it's definitely getting smaller and parts of it are starting to get pale and look more flesh toned. We're being followed by a pediatric plastic surgeon and so far it's been the wait and see approach. The specialist did say that once it had involuted, he might need minor corrective surgery to fix any left over sagging of the skin.
Me - Aimee - Spot on liver
Elliot, 9/20/06 - H on back (nearly gone)
Felix, 7/28/08 - H on forehead (in involution)
Taking the 'wait and see' approach, for now.