Everyone's made such great comments already in this edit exercise, and Jami's made a few great changes, so I don't have much to add (except this is a great exercise for writing groups!). Also, notice how each of us might see something different to fix. Hmm. It takes a village to revise a paragraph?
She cringed at his perfectly innocent question. Before he noticed, she quickly faked another yawn and covered her face with her hands. Sharing the reasons she’d stared at the ceiling for hours last night would only add to her guilt. It was bad enough that she’d dreamed about her ex-boyfriend, Daniel. Add in his command that had burrowed into her thoughts – ‘Come to me’ – and it would sound downright horrible. Instead, she offered, “Uh huh.”
Okay, I'm one of those who has to sleep 10 hours or I yawn the whole next day, so I'm not clear why she had to fake a yawn if she hadn't slept well. But beyond that=
Before he noticed, she quickly faked another yawn and covered her face with her hands.
Can you clarify with some transitional word? I mean, is she faking the yawn SO she can cover her face then? Why are those two actions together? See if you can make the connection more than they happen about the same time.
Sharing the reasons she’d stared at the ceiling for hours last night would only add to her guilt.
Sharing with whom? I'm saying that because, though of course the reader will know that from earlier paragraphs, you might want to have a bit of emphasis. It's not just sharing, but sharing WITH HIM. We all know that as soon as he's gone, she's going to be on the phone with her best friend. "You would never believe what I dreamed last night!" She won't mind sharing with her... it's the current bf she doesn't want to share with. So think about putting his name after-- Sharing with Joe the reasons....
It was bad enough that she’d dreamed about her ex-boyfriend, Daniel.
Don't use a comma with a "name appositive" like Daniel there. An appositive is a word or phrase that explains more about a noun, and generally, yes, you set it off before and after with a comma (no comma at end of sentence, of course)-- I went to Chicago, my favorite US city, to visit Theresa. You don't use a comma usually with a name or a one-word appositive (her coach Joe Parcells/ the color purple). So:
It was bad enough that she’d dreamed about her ex-boyfriend Daniel.
Add in his command that had burrowed into her thoughts – ‘Come to me’ – and it would sound downright horrible.
I'd put "Come to me" in italics, to distinguish it from the real dialogue that follows. As it's not vocalized (it's in a dream), I think we can get away with italicizing as we would thoughts.
Whenever you use "it," think about what "it" refers back to. There isn't a clear antecedent there, so I wonder if you can recast that? I can't actually come up with an alternative, but put your mind to it and see what you come up with. That's two sentences in this paragraph I've ended with a preposition. Don't follow my bad example. :)
Instead, she offered, “Uh huh.”
Instead of what? See, where that's placed suggests that "instead of doing A, she did B"-- it's what we call a "sentence adverb" which modifies the whole sentence or clause, rather than a verb (as adverbs usually do). "Additionally, I will sing The National Anthem" is an example of a sentence adverb-- It's not "I in addition to dancing will sing," right? When you put an adverb at the start of the sentence, removed from the verb, usually you're saying it's a sentence adverb. Okay. What I'm getting at is I think you want it to be, uh, the direct object (that is, not a modifier at all, but a noun). Okay, that all sounds weird, but understand, some words can be different parts of speech depending on where you put them, and depending on the role they're playing in the sentence. So words like this have to be placed especially carefully. In this case, I think you mean "instead" as "instead of that other thing she could be saying"-- that is, a noun phrase that is the object of "offered". So "She offered instead" might be more correct.
Finally, this is a long leadup to an uninteresting line of dialogue. But maybe that's what you want? It's sort of funny, really, that "uh-huh" is all she can manage.
But that come to me is so sexy, and it's sort of buried in the middle of the paragraph. Is it important, like is she going to have to go and find Daniel? If so, I'd really suggest =that= line is what the paragraph is about, not about the heroine saying, "Uh-huh." I guess you might want to assess what's important in this paragraph, and make the last line in the paragraph reflect that important aspect somehow. How could you do that? Well, now really, I might be entirely wrong about come to me being important-- I'm easy to seduce, obviously-- but if in fact that's important, try putting it at the end and go back and build the paragraph towards that.
Just an example of rearranging:
She cringed at his perfectly innocent question. Before he noticed, she quickly faked another yawn and covered her face with her hands. Sharing the reasons she’d stared at the ceiling for hours last night would only add to her guilt. So she offered, “Uh huh.” It was bad enough that she’d dreamed about her ex-boyfriend, Daniel. Add in his command that had burrowed into her thoughts – ‘Come to me’.
Okay, obviously it needs some work. But think about what you want to lead to, and if it's not that "come to me," ignore me. :)
Just everyone keep in mind -- a paragraph is a unit of meaning. It has some purpose beyond just grouping sentences together. When the paragraph ends, the reader should have advanced to some additional understanding-- maybe not a radical advance, but an increment. That this is a paragraph, that these actions and events and reactions are grouped together adds some meaning. And where you end the paragraph adds meaning too-- you're saying, "This is what all this has been leading up to." (Another ending preposition! Arrgh!) There's a dramatic pause in there, just by the line ending and the white space of the next paragraph's indentation. So when you end the paragraph, you're identifying what's important, what the reader should pay attention to. (Eeek. Another one. You can tell I'm tired. I can't figure out how to fix those.)
You can reverse this to bury a clue, btw. If you hide the clue in plain sight in the middle of the paragraph, the reader can't say you tried to trick her.
I think also you can manipulate this expectation for comic effect, by ending as Jami does on something anticlimactic.