my baby has the flu!!!

Annabela
My LO has the flu!! He finally said mama but it's when he's not feeling good or just wants to cuddle. Doc didn't give us any medicine so we are relying on advil. His fever was gone for about 24 hours and he was great except for a cough. This evening his fever came back! This is the first time we are dealing with a fever. At what fever should we be calling the doc again? FTM