I wouldn't have reintroduced the paci if it's been that long but since you have, I suggest waiting until this period of discomfort has passed and when he seems like he's back to more good days than bad, take it away again. He will cry a few nights but it will pass and he will become a better sleeper when he learns to sleep without it. At least that's what happened with DD. We just took hers away last week and she used to wake twice during the night for me to come find her paci and give it back to her. After taking it away, she woke up twice that night and I went in the first time to let her know I was there, but I didn't go in the second time and she fell right back to sleep on her own. And by the 2nd night sans paci, she was back to STTN - no waking! She's been doing great ever since.
I tried just cutting back on the paci and using it just for sleep but she would cry for it throughout the day so when I finally just took it away completely, it's like she just figured out that it wasn't an option anymore.