...the author could write, "You're making me mad - I did clean my room!"
which, sadly, creates an instance of a
tell-don't-show, called in the screenwriting craft
"on-the-nose" i.e. subtext-free dialogue, which is what every good writer supposedly strives to avoid.
The trick is to convey growing anger without resorting to overused visual cliches: narrowing of eyes, gritting of teeth, general agitation, or flushing of the face, which latter risks spoiling the read of dark-complected readers who till that point might have formed a different conception of the character.
This is an opportunity to economically reveal or reinforce character & relationship by tag verb alone: growled, muttered, sneered, shouted, blurted, grated, whispered. Again, sometimes
said just won't do, especially for the MG demo.
Even italicizing the
did can convey the speaker's feeling put-upon, perhaps after having been called a liar on one or more occasions.