Finally happened...I feel so bad/worried

My almost 7 month old boy has a pretty bad fever for the first time ever. It came out of nowhere. He was fine ALL day yesterday and then at 11pm on our drive home from a friend's house my husband and I noticed he was REALLY hot. I figured the car ride was just too hot so I undressed him down to his diaper but after a little while I realized the "hot" wasn't going away.

I tried wiping him with a cold cloth but he hated that. I eventually gave him a bath and that helped a little. I also gave him children's Tylenol & was told by the nurse hotline to not worry too much so long as he didnt stay at 104 degrees. It is now 6am (7+ hours) and he is still "hot." His temperature has been ranging from 101 to 103. He did reach 104 last night but that was before the bath.

I have no idea what brought this fever on since he was perfectly fine all day yesterday up until the car ride home. I am freaking out because he's still hot and my poor little guy is not happy.

What do I do? Take him in to urgent care? Or wait it out?

Thank you.