From Longman Dictionary of Contemporary Englishscrunch something ↔ up phrasal verb informal1 SQUASHto crush and twist something into a small round shape I scrunched up the letter and threw it in the bin.2 scrunch up your face/eyes to move the muscles in your face in a way that makes your eyes seem narrow He scrunched up his eyes and grinned. → scrunch→ See Verb table
Examples from the Corpus
scrunch up• They are smooth and stiff but will serve if I scrunch them up before use.scrunch up your face/eyes• They scrunch up their faces, peering into the haze. 