区别就是两者意思是不一样的。且所指的人体部位也不同

forehead中文意思是n. 前额

brow中文意思是. <文>额眉毛坡顶（从船到岸上的）同。跳板

A frown creased her forehead.她一皱眉，额头显出了皱纹。

Her brow furrowed in concentration.她眉头紧锁全神贯注。

He wiped his brow with the back of his hand.