V.G.
My son would get a fever just in the evening and during the night too when he was teething. It was nerve-wracking, but nothing else was wrong so I just made sure he was comfy during the day and had a cool washcloth or cold chew toys to gnaw on.
I wouldn't give him any pain medicine unless he's obviously in pain from it because it can be really hard on a babies digestive track and their kidneys/liver.
Sounds just like teething to me, and if he's not acting sick or coughing or throwing up, I wouldn't take him in. Drool is another telltale sign of teething, too.
Good luck, he'll get past it soon! :)