Press in the pot fixes this. When you go to press the cheese, put something in the bottom of the pot to keep the mold up off of the bottom. I have a little wooden thing that my husband made for me about an inch tall. Then you pour warm water, from 110 to 120 degrees into the bottom of the pot, not any warmer than that, but do not get it high enough to get to the cheese. Put the cheese in the press and wrap the top of the pot with a towel to hold the warmth in. After your first flip, replace the warm water. After that, leave out the water.
This was not my idea, it was Sailor's, and it works great. You are keeping the curds warm enough to knit, but you don't want to keep them warm for too long because they would still be producing lactic acid. The first two presses always work out well for me.
Until I read this on this forum, I had a lot of ugly cheese. Delicious, but ugly.