Correct

发黑

/ fà hēi /
Strokes

Example

As a Verb

turn black/dark

1
de
yǎnquān
眼圈
hēi
发黑
  

There appeared some dark rings under/beneath her eyes.

As a Verb

have a blackout; black out

2
Yǒurén
有人
击打
de
hòunǎosháo
后脑勺
  
,
xiàzi
下子
jiù
liǎng
yǎn
hēi
发黑
le
  

Someone hit him on the back of the head and he blacked out immediately.

3
liǎng
yǎn
hēi
发黑
  
,
néng
kāichē
开车
  

He can't drive because he suffers from blackouts.