That’s what small men do. The only thing we hate more than a sore loser (e.g., Trump in 2020) is a gloating, ungracious winner. Amazingly, Trump manages to have been both.
In the meantime, or if your grinding seems to be associated with periods of high stress or poor sleep, an over-the-counter mouth guard might help as a short-term solution (two weeks to a month).
Your son is almost certainly going into puberty, which would explain why he is starting to grow now. Both boys and girls show changes in their breasts at puberty. The areola or area around the ...