Going through the exact same with my LO and he's only 12 weeks tomorrow!
We've had three poos today so far and normally, would only have one. He's drooling all the time and I think I can feel sharpness beneath the gums. He's actually been really unhappy today and I tried a little dentinox on his gums and it seems to have helped.
I did google bowel movements and teething and apparently, they poo more as there is extra saliva that they swallow and it isn't digested, so just comes right out the other end.