I'd say OT from the teething esp. if he was high sleep needs before. But that's just a thought. Also a longer, more mellow wind down if you can do it. I found DD really needed to change up her routine around this age and sloooow it down a bit more. A bath, some lotion on her, a few books to read, a song, all in dim light in her room, adding music back in for her to sleep too as we had when she was a baby. These things all helped at the time she was really driving us bonkers.