I have no idea about the puffiness but i can tell you i am one of those kids that is not normal.
Just recently I got nervous at work as i get stressed out and ina big group. I start to heat up and feel like i am going to blackout or pass out they feel the same to me. The only difference this time is i didnt blackout but the right side of my face was so red that it felt like someone was burning me. They asked if it was a sun burn but i wasnt outside all day and i knew it was because i was getting pressured to talk to people with others around which increases my nervousness and increases my internal temp.
I now have twitches in the area on my face that was beat red and have had them off and on since friday. i am worried i am getting worse. I am not sure about my protien levels but like you said with PKU it is hard to follow has most if not some of the doctors still do not know what is going on.