D.W.
Yes, it can cause damage. If the soft spot closes too early, the brain does not have room and the skull can not grow properly. The baby has a soft spot in the front and in the back to allow room for skull and brain growth.
Your son will need to see a neurological surgeon as soon as possible to determine what will be the best course of treatment to correct this.
But rest assured that many children do thru this and do just fine! I had a little boy in my moms group that he needed the same type of surgery at about 6 months old and you would have never been able to tell if the mom didn't tell you!