OK! I had this problem with flushing face as I described before in my previous posts on this thread.

Some anxiety made my face go red and it only happened in classroom where there was lesser oxygen and never outside. So the problem was with oxygen or with the heat as my body was trying to cool down the blood by widening blood vessels in the face. What helps me prevent the flushing face was decreasing the amount of milk I drank. Milk could have cause more mucous to form. Secondly, I started to make my own kefir which might help by increasing bifidobacteria and decreases ammonia. And thirdly, I started to consume raw eggs. Vitamin A or other nutrients ?

I hope it helps.