Tug and Twist - ouch! Regression help (3 weeks)

My little one has been a nipple mangler from the get go. We saw a wonderful lactation consultant the first week and things seemed to go well for a while after that - with my help, he could get a good latch and things were starting to heal. Then on week 3 he decided to start clamping down, pulling back, and twisting his head - ouch! At first I thought it was because I had a fast flow and he kept choking on it, but now he does it all the time. I can't even get him to latch properly anymore - he keeps his lips closed small refusing to open wide no matter what I do, and if I help him along with it, he'll just readjust himself to small mouth mid-feed over and over and over. I've never given him a bottle or a pacifier (except once in the hospital becaue of a nurse who didn't listen to my request). Any advice??