Of course the jaw muscles grow but to think that getting bigger muscles in Your face is gonna make your actual face look more masculine Idk..The growth of the cheekbones jaw and nose during puberty is from testosterone. Guys with large features, wide faces, and dimpled chins are genetically superior. Only a make in tip top condition can generate high levels of test. Tough to say if taking exogenous test will translate to more a masculine bone structure after being fully grown, same reason some guys get deeper voices after starting gear and some.guys don't.