pucker

(noun) an irregular fold in an otherwise even surface (as in cloth). Synonyms: ruck.

(verb) to gather something into small wrinkles or folds. Synonyms: rumple, cockle, crumple, knit. Example: "She puckered her lips."

(verb) draw together into folds or puckers. Synonyms: gather, tuck.

(verb) become wrinkled or drawn together. Synonyms: ruck, ruck up. Example: "Her lips puckered."