I do not know the exact date or year when he got his nose job, however, it was after he graduated from law school, as his "old nose" is prevalent in his graduation pictures. Veneers are very common, and unless you look through a plethora of dated pictures or obtain his dental records, it would be difficult to pinpoint when he got them. As far as skin whitening, again, I do not know any dates. Usually skin whitening is done over an extended period of time, with multiple treatments. This wiki article may give you some info about methods that can be used: Skin whitening - Wikipedia, the free encyclopedia
Check out the link below. It seems that Barack isn't the only Obama to get a nose job. http://4.bp.blogspot.com/_u3lFqBksmr...d-now_full.jpg
It is also suspected that she gets regular Botox injections, had a mini facelift, and the possibility of cheek implants is highly suspect. She also has veneers like her husband.