Wrinkle, crease (6)
I believe the answer is:
pucker
I believe this is a double definition.
'wrinkle' is the first definition.
(I know that pucker is a more specific form of the action the wrinkle)
'crease' is the second definition.
(I know that pucker is a more specific form of crease)
(Other definitions for pucker that I've seen before include "Gather into bulge, say lips" , "Wrinkle - draw into folds" , "Gather skin into folds" , "Purse lips, or gather into wrinkles" , "Gather into wrinkles, cause lips to bulge" .)