No other hidden cuts or infections? My big one is too old for screaming (she's at the whine and complain age) but sometimes she gets tiny cuts or splinters on her feet (sometimes hands, sometimes gravel embedded in her knees, then this one time she got gravel embedded in her forehead), they get infected and they hurt like hell but don't give an all-over fever. Upset tummy/gas would do it too.

Hope she's better today.