I'm assuming that each change was beneficial enough not to crush the user under the weight or poison him with the metal. There would likely be far more useful elements like spidersilk or Graphene but I'll just go with it and assume metals were the better choice at the time.
I would also assume it's going to be a metal skeleton or rather a skeleton that has metal worked through/around it as the thinness of a metal skin and the speed with which it creases and breaks would be too high.
1: Society would change it's diet, with each diet being aimed at metal intake based on the metal (or alloy?) in their bodies.
2: people would weigh more and structures, cars etc would need to change with it. Large-scale paving or otherwise strengthening the ground would happen as walking across soft ground would be more hazardous, and our walks on the beach wont happen anymore due to the loose sand.
3: people with "good" materials like Titanium would have a higher status as they can handle more while still being light, but only if they can keep an expensive diet and supplements to keep their titanium level up. Lucky people will jave abundant and cheap materials for a skeleton that is still light and strong.
4: electric cirquitry would be more secure than ever. Someone lined with copper or other highly conductive material would have both an advantage as electricity would get less time to heat up bodily tissues or damage nerves, but they would also experience more electric mishaps. Probably no wireless charging for these people!
5: currently surgical metal is removed from the body as soon as it has served it's purpose as during accidents the metal will bent when the bone breaks, this ensures malformed regrowth so society will be absolutely careful to prevemt broken bones as it makes it so likely that you'll BR horrifyingly disfigured for the rest of your life.