Fortunately, where you have the stretching occuring around the jaw and chin, it looks fine. The way the natural hair flow-patterns occur on men's faces looks very much like that. In my opinion, your fretting over nothing. It looks great so far. the only things I'd change, is I'd tone down the reds on his cheeks slightly, (he looks a bit weather bitten). Also his naso-labial folds, (smile lines), seem to be riding halfway up his cheeks. Keep working on it, it's looking better all the time