K.L.
First of all, its an old wives tale that teething causes fever - fever is caused by the body fighting off infection, not cutting teeth. We all learned this teething/fever story from our mothers and grandmothers who brought that story from their childhoods when they also thought that being out in the cold can cause one to catch a cold (also not true, as a cold is caught only if one comes in contact with the virus!). So, forget that he is teething - it is just going to make him more unhappy because he does have a fever, but know that the two are NOT connected.
As far as the fever goes, it can get as high as 105 - if it gets to 105, THEN there is a chance he could have a febrile seizure and you should take him to the ER. But young children and babies often get really high fevers when fighting off an infection, so don't really start to worry unless the thermometer gets up there in that 105 degree range. To keep him happier and cooler, give him children's Motrin as opposed to Tylenol - it gets that fever down much faster and better than regular old childrens tylenol (ask your ped, and he/she will likely agree! Its what my ped has told me). Give him tempid bathes during the day - like luke warm, a little on the colder side than the hot - it let him play in it. Wet his head and it well help bring his temp down and cool his body off.
Try to let him sleep in his own bed if you can - if you dont already use one, just keep a baby monitor on and check on him as often as you'd like. He will probably sleep really well as long as he gets a dose of motrin before bed - that usually lasts long enough to make his fever go down to a comfortable level, makes him a little bit extra sleepy so that he will get some comfortable hours in. There is no point in having him sleep in your bed, or you freaking out about this - fevers happen, and will continue to happen throughout his childhood, so its important that you get some rest to in order to be able to support him through the day. The motrin will help his teething alot too - I also reccomment baby orajel for quick fixes.
When my daughter had roseola and spiked a high fever, I did all of these things above - I also bought all sorts of apple juice, little bottles of water, gatorade and pedialyte pops to keep as much liquid in her as possible (helps with the fever greatly). I let her run around the house in only her diaper, gave her cool bathes, and even bought an empty spray bottle so that she could spray herself if she wanted.