1590s, intransitive, "become irregularly ridged or wrinkled," possibly a frequentative form of pock, dialectal variant of poke "bag, sack" (see poke (n.1)), which would give it the same notion as in purse (v.). OED writes that it was "prob. earlier in colloquial use." "Verbs of this type often shorten or obscure the original vowel; compare clutter, flutter, putter, etc." [Barnhart]. Transitive sense of "draw up or contract into irregular folds or wrinkles" is from 1610s. Related: Puckered; puckering.
1726, "a drawing or gathering into folds or wrinkles," from pucker (v.). In 18c.-19c. sometimes also in a figurative sense, "state of agitation, condition of excitement" (1741).