Does he have a lovey?
If not, let him have one.
My son, was about 3, when we took away the pacifier. Cold Turkey. We explained, Santa needed them to help the other kids. With him, he rounded up all the pacifiers. Put them in a bag to 'mail' to Santa.
It took him 2 days to adjust.
BUT he also had a lovey he sleeps with.
My son mind you, was a constant Binky user. ALL day. Not only at sleep times. ALL day. Hard core.
For my son too, his mouth was getting malformed by the Binky. When his mouth was closed... it would not shut/close all the way. There was a space between his upper and lower teeth, in the shape of the Binky.
Which, per the Dentist, can take 6 months to 1 year, for the mouth/teeth to revert back to a normal formation. Which, thankfully, it did, in my son.
SO.. you might want to check the "bite" of your son's mouth. Too.