how to tell if i have a fever
1. Take your temperature if you have a thermometer. If your temperature is 103Â°F (39.4Â°C) or lower, try to treat the fever at home, seeing whether it responds to at-home care. If it's 104Â°F or higher, call emergency services or go straight to the emergency room; you may need immediate medical attention. If you're trying to diagnose fever in someone else, try feeling the temperature of your own skin and then quickly checking the temperature of the person in question's skin. 2  This should give you a good comparison for whether the person is feverish.