Accidental milk challenge test with NO reaction

The last time I tried to do a challenge test with my oldest son (now 14) with 1/4 tsp. of baked milk, he broke out in a rash the next day all over. So, I decided to not re-test him for a while. Recently, I was making corn bread muffins for a friend with a rice allergy. Since I only had rice milk and cow's milk on hand, I made her batch with the cow's milk and ours with the rice milk. I set the pans of corn bread to the side and left the kitchen. My teenager, who love to "test" things, ate three slices of cornbread from the WRONG PAN. This gave him an equivalent of 3 T of cooked cow's milk. I decided that it was a good challenge test, so rather than rushing to get Benadryl, I just watched him on and off for 24 hours. Nothing. No rash, no hives, no digestion issues, nothing. He is so excited that he wants to go straight for cheese (yeah right). I think that I may try once again to start introducing baked milk a little at at time. Although I am fine if he doesn't have dairy the rest of his life, I hate worrying about if he'll be okay in college or when he's on his own. I also feel for his future wife. There are so many hidden sources of dairy, and he has had so many bad reactions in the past. It would be nice to see if he could at least tolerate those hidden sources and baked sources, even if he never is able to have cheese. (Although, he REALLY wants to have cheese:)). I'll try to log in some of our testing and give updates. Yeah for cornbread!