1HBH [intransitive and transitive] also wrinkle up
if you wrinkle a part of your face, or if it wrinkles, small lines appear on it:
Alex wrinkled up her nose at the smell.
Carter wrinkled his forehead in concentration.
His brow wrinkled when he saw us.
if a piece of clothing wrinkles, it gets small untidy folds in it [= crease]:
The trouble with linen is that it wrinkles so easily.