Is a blunt paint below the hinges of my jaw indicative of swollen lymph nodes, therefore I ought to bunker down and get rest/fluids/etc?

See Doctor. Pain in the jaw hinge could be tmj, but pain below the hinge could be anything: referred pain of decaying tooth, inflammation in the parotid gland or lymph node. If red, warm or swollen, call your doctor. Rest and fluids are for viral infections (cold and flu). If this is a localized bacterial infection you need to seek medical attention.