Girls, the baby is 3 months old, has a fever, especially the cheekbone…

Girls, the baby is 3 months old, has a fever, especially the cheekbones, but there's no temperature. I stroke with my hands and lips - it feels warm to me, But I put an ordinary mercury thermometer in the armpit and see that the temperature is normal... I'll say right away, I'm panicking, so I measure with two mercury thermometers). There's no cough or runny nose.