You'll never look at your hairline again in the same way.
Picard is telling Jason that now that he knows that Picard is his father, he will never able to look at his hairline in the same way. You would think that if they could build ships to travel to the other side of the universe, cure every disease, end hunger and poverty and come up with a holodeck that they would have come up with a cure for baldness. Lame. Priorities all wrong.