My baby boy (13 days old) has a lump on his head. It feels like it is full of fluid and he developed this lump soon after birth. He was delivered through a C-section because the contractions caused his heart rate to drop. Will it go away and after how long? The hospital said not to worry but I am worried.

Is it red and raised? If so, it could be a hemangioma, or a stork bite.

Hemangioma - Wikipedia, the free encyclopedia

MedlinePlus Medical Encyclopedia: Stork bite

Sadly, we can only guess, it will take your doctor or another medical professional to go you a valid diagnosis. The above are just guesses.

Good luck.