You've got a run-on sentence and an unintentional sentence fragment and a physical impossibility.
If I may fiddle with it a little?
A paint brush crashes to the floor, splattering paint.
Dammit!” The artist shakes her fire-engine red locks and stomps off to the kitchen. A moment later, she stomps back, sipping a soda. Her lower lip juts out in a pouting manner.
OK, that fixes the grammar and punctuation issues, and smooths it out some. I made the assumption that she says "Dammit" in response to dropping the brush, which is why I changed the order of sentences there, but it's possible she might have said "Dammit" about something else, which in turn caused her to drop the brush. In that case, "Dammit" should be first, but then that raises the issue of what caused her to say it and that's not shown.
In terms of the subject matter, I don't know why the first few sentences need to describe a pissed-off woman fetching a soda from the kitchen. I could be wrong, but this strikes me as really insignifcant action. A story should start with A and go to B and C, not start with A (assuming the fallen paint brush is A) and wander off to somewhere backstage before returning to pick up the dropped thread of the story.