My MC, first person narrator experiences a moment of embarrassment. There isn't another character on hand at the moment to observe that she's blushing.
I wrote: I blushed to the roots of my hair.
Now, I have been very careful to not have her say anything about herself that she doesn't know for certain. I have been careful not to have her know the thoughts of others and I haven't planted contrivances to have her say things she she can't otherwise know. In this situation, the only other person around is asleep.
The question is, can a first person narrator make a statement about herself that she knows happens generally, but doesn't know for certain that it happened in the instance she says it? She can't see herself blush; she can feel it, though perhaps not to the roots of her hair. Is it OK to say this as one of those hyperbolic statements we all make?
I can rewrite it many ways, it just made me wonder what others think since it was kind of bothering me.