yay for a better nap - sometimes it really does take a several days for new A time to result in sleep changes. Sorry about the bad night - teething can indeed mess everything up. If it's not too late for today, I'd just shorten his next nap - wake him after 1.5 hrs since the first nap was so long.
And yes, the first nap of the day is often the shortest, but....if his 2nd nap is long after a good first nap and the same A time, I wouldn't adjust it. If he doesn't seem like he's ready to go down after 2 hr 40, then I'd add 10 min or so.