what does it 'want' to say? it seems to say what it says about lovers mussing each other's hair..
it could also be euphemistic, I can't tell what the dream(s) have to do with it without seeing this 'quote' in context; it could
mean that the dreamer was dreaming of being ravished by their lover.
using a rare 'opposite' of unkempt makes me think this author wasn't being very serious; see Quinion
and How I met my wife
edit: I assume that this is the source of your quote:This is my dream,
It is my own dream,
I dreamt it.
I dreamt that my hair was kempt.
Then I dreamt that my true love unkempt it.
Ogden Nash was well known for his humorous poetry.