9 month old fever and no other symptoms??

Arielle

So my 9 month old has had a fever for about a day in total, tonight will make 48 hours, pretty low grade otherwise though, only one reading of 103. He’s eating and acting fine and active, ears don’t seem to be bothering either, just random fever, no cold or flu symptoms, when gets to about 102 he gets cranky and whiny so I give him Tylenol, then he’s fine again after an hour, other than disrupting his sleep schedule, he did manage to sleep a full 7 hours last night which was a first I’m general for him. Was happy when he woke and his temp was 97, until he woke up just now and temp is at 101 again, what the heck is going on?