swollen head别理解成“头肿了”，其正确的含义是：自命不凡，自负，神气活现。

【例句】
Don't compliment him any more, or he'll get a swollen head.
不要再表扬他了，不然他就找不着北了。

Janice has had a bit of a swollen head ever since she got that promotion.
自从Janice升职以后她就有点自命不凡。