A cold washcloth that he can chew on. I put it in the fridge when he was younger but now I put it in the freezer

You can try massage his gums. And just wait!

Maybe try a bath. If he's got a fever let him just hang out in a diaper and just make him as comfortable as possible. My daughter got clingy when she would teeth so we would snuggle a lot. Keep your head up momma it gets better