R.H.
I keep one of my daughter's pacifiers in the freezer. When she gets really fussy with her teeth I pull it out, the cold 'shocks' her into stopping crying and then soothes her. works every time. You'll probably get mixed views on baby oral-gel but I've used it a couple of times and it works for a little bit although it can be messy. Try a little before putting your son down for a nap. And don't fret, he'll get back to a better sleeping pattern soon enough. My daughter was doing the same thing and now she's back to her 2 hour and 1 hour naps.
R.