K.R.
Hi A.,
I had tubes put in my ears when I was very young, but only after years of chronic infections. Because they waited so long to do the procedure, I lost 20% of my hearing and developed an allergic reaction to the cillin family so know that you are doing the right thing for your son. Once he comes out of general anastesia, he won't be in any pain, but he will be very out of sorts. He won't know where he is and will be very confused so expect some/lots crying. I had absolutely no pain though when I woke up and the tubes were already in place doing their thing.
I can't exactly recall how they are put it, however, I can tell you that to remove them, all the doctor did was poke something in my ear which caught the tube and pulled it out of my ear while I was awake- didn't hurt a bit!
As for the dairy, that might still be a good thing to limit/eliminate because of the congestion it causes in some people. I'm not sure about the excema connection but hopefully you are able to keep that under control as well. I'm sure you're scared but having been on your son's end of the issue, you are doing the kindest thing for him by eliminating the excruciating pain of the ear infections. GOOD LUCK to you both!