A flash of surprise momentarily showed in her eyes.
Tips
memory
闪 ('flash') + 露 ('to reveal / show'). The compound captures something visible for only an instant - a perfect verb for fleeting expressions, glimpses through fog, or split-second tells.
register
More literary than spoken. In casual Chinese, 闪过 or 露出 cover similar ground; 闪露 sits comfortably in fiction or descriptive writing.