My plastic surgeon says that laser can selectively penetrate skin and make me look young. Is this true?

Bullshit- this doctor is FOS. There is no treatment, laser or drug  that which can selectively penetrate skin and only affect certain tissues. All laser does is heat up the deeper tissues. In some lucky people, this results in a smoother and well-toned skin. However, this is not a universal benefit. Most people either find no benefit and others are burnt from the laser.