have a swollen head
To be conceited, arrogant, or self-aggrandizing. Janice has had a bit of a swollen head ever since she got that promotion. John has such a big head on him. All he ever talks about is himself.
swell out
To bulge or protrude outward. The spot on his head swelled out where he had been hit by the baseball. After the flooding, the walls in the basement began swelling out with excess moisture.
swell out
to bulge outward; to expand outward. The sides of the box swelled out because it was too full. The west wall of the garage swelled out just before the building collapsed.
have a swollen head
be conceited.