Hearing the comment, his face turned a sudden red with anger.
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艴 is bound to the compound 艴然 ('with a displeased / angry look'). The famous attestation is 《孟子·公孙丑上》 - 曾西艴然不悦 ('Zeng Xi looked sharply displeased'). The same compound also reads 艴然 in some older dictionaries - both readings are attested.
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Pure classical / literary. Modern equivalents: 怫然 (same meaning, written with the heart radical), 勃然大怒 (to flare into anger). You'll see 艴然 almost exclusively in classical Chinese textbooks and elegant essays.
Right 色 (Kangxi #139, color / facial expression) anchors the meaning in the FACE: the change of complexion that betrays displeasure. The same radical drives 艳 (resplendent) and 艰 (difficult - same indexing tradition though etymologically separate).
