"The skin tightened in his eyes"?

This phrase likely means that the skin around his eyes became taut or stretched, possibly due to a strong emotion or physical sensation. It could indicate that he was experiencing intense concentration, surprise, fear, or another strong feeling.

The phrase "the skin tightened in his eyes" is a literary representation of someone's eyes narrowing or becoming focused. It suggests that the person is paying close attention to something, or is concentrating intently.