Not something that us blokes tend to worry about (on a vanity or self confidence point of view, perhaps if it was needed for health or medical reasons) But, I know guys who have had botox at 30ish years old because of frown lines and stuff like that. And, my mate is a boxer, he had his nose done as it had been broken twice. I dont know how I would feel if I was really depressed over my image and wanted something smaller or something bigger etc, I think if it takes over your life to the point where your body image is the root of a lot of stress and your lifestyle would improve as a result, why not? Sometimes its a mental battle and people will see nothing wrong at all with you!