My cheek suddenly swelled up a lot.

Sudden swelling of the cheek is most likely a sign that inflammation from a tooth root or the gum has developed into an abscess, so come to the clinic right away rather than waiting. An abscess does not resolve on its own; it needs drainage, treatment of the tooth responsible, and antibiotics if necessary. In particular, 1) swelling reaching below the eye or into the neck, 2) fever or difficulty swallowing or breathing, and 3) difficulty opening the mouth are emergencies that can develop into a systemic infection, so go to an emergency room even at night or on a holiday.