Is there anything I can do?
Yes, deep breathing, counting to ten, the "this will pass" mantra.
I know it's hard, I know!!
Unfortunately molar cutting plus 2yo birthday developments can both go on some time. If there is a level of BT resistance you just can't cope with then I suggest moving BT 30 min later and see if it helps. I also suggest readying yourself for BT so I used to get my things ready prior to the WD routine. I used to put a cup of tea or bottle of water, a good book and something comfy to sit on (I sat on my bed which is within verbal reassurance distance from DS's bed) ready before I even started WD. Then at the end of WD I didn't even go downstairs, I just camped comfortably outside his room. If needed of course I went back in, otherwise I repeated over and over "go to sleep" or "I'm right here, go to sleep" or "everything is okay, go to sleep" (see the pattern).
I think if he is sleepy random times of the day it would help to get back on track with a fixed nap or fixed quiet time for cuddles and book or quiet TV programme, relaxing music, whatever you are happy to do.