Was Helping To Squeeze A Pimple. Ask To Breathe By Mouth, Which He Didn't. Vomitted & Fainted. Problem?

Tonight before bed, I was helping my 12 year old son squeeze a pimple on his nose. I was pressing on his nose a bit and told him to breath through his mouth. He told me he was afraid to breath my carbon dioxide. I assured him that wasn't an issue. I guess he didn't believe me because soon after he said it hurt a little from my squeezing, he looked upset and said he was tired. I didn't understand what he meant. He just kept saying he was tired. He looked a bit faint. At that point I realized he was going to faint and I caught him before he fell into the toilette. I got him to sit down and he threw up on the floor. He looked drained of his color. After a little while, I stayed close while he washed up in the shower. He got dressed, got a drink, and I put him to bed. Before he went to sleep I asked him if he felt sick or if his head hurt. He said he felt okay. He has never fainted before and I'm just wondering if this was conditional or if it points to a more serious problem. Also, is it normal to vomit after fainting?