My son had a huge mass on the back of his neck, it was golf ball sized. They removed it probtly. I think it was a few days till they could get us into outpatient and they wanted two ped surgeons there to remove it. Well he turned blue and was so pale. They thought that was the case but they found out during his work up that he had two holes in his heart, an artery that should had severed at birth and VSD. Well it turned out all the heart problems were causing the sweating, blue color and pale... not to mention the failure to thrive. The mass wasn't helping but the heart was making it terrible. Although I was told if he turned blue to rush him to the ER. I'm suprised you didn't. You should have at least called. That is very dangerous. If before Monday anything like that happens run not walk to the ER. He isn't getting enough oxygen. Like I said I'm suprised you weren't told that.
But now that his mass is gone he is doing much better. He's back on his curve but that is 4 surgeries later. So you might have a long road ahead of you. Took 3 surgeries to get the mass completely out. It kept growning back. He had to be aggressive for it to be gone.