With my first daughter, I seem to remember teething issues going for about a week at a time. I have no idea if that's the "norm" or just us.
A lot depends on how high the fever is. Is he running a low fever or is it spiking up to over, say 102/103?
If you like and trust your ped, then you can always give them a call and ask what they recommend. My pediatrician doesn't tend to suggest medicating low grade fevers, but wants me to give her a call if either of the girls' temps get over about 102. That way, there's just a heads up if something needs attention later. (My first daughter would spike fevers to over 104 when she was a baby.
So, I try to keep an eye on temps when either of them are under the weather.)
Hope he feels better soon!