swelled head
US /swɛld hɛd/
UK /swɛld hɛd/

1.
grosse tête, vanité
a person who has an exaggerated opinion of their own importance, ability, or attractiveness
:
•
After winning the award, he got a bit of a swelled head.
Après avoir remporté le prix, il a pris un peu la grosse tête.
•
Don't let success give you a swelled head.
Ne laisse pas le succès te donner la grosse tête.