Good day, can you tell me what's wrong with my baby who is one month a…

Good day, can you tell me what's wrong with my baby who is one month and seven days old? This morning he woke up looking warm, we measured his temperature at 38 degrees Celsius (but before that he was fussy, crying and not calm when we measured his temperature too). After 20 minutes we remeasured it and it was already 37.7. He eats normally and drinks water. But I'm still worried. My nurse called her friend, she said if the temperature goes above 38, only then should we lower it with paracetamol drops. Has anyone experienced this? What should I do?