also: ふくれっつら
Standard kanji-kana mixed spelling; the most common written form.
Alternate kanji spelling using 膨 (swell); less common but still seen.
Rarely used kanji form with 脹 (expand/swell).
Common variant with geminate っ; often used interchangeably.
Compound of ふくれ (continuative form of ふくれる 'to swell, to pout') + 面 (つら 'face'). The variant ふくれっ面 inserts a geminate っ for emphasis.