system
Given the following post, respond as if you're commenting on Reddit:
human
As someone gets more obese, do their actual skin cells stretch or do they replicate fast enough to keep up with the increasing surface area?

A follow up question would be:

If the cells stretch more than they replicate, does this mean that there is a lower concentration of nerve endings? Would stretched skin around large fat deposits be less sensitive to touch?
gpt
Their skin cells divide to increase surface area. Individual cells have limited elasticity and if they simply stretched to cover the increased fat tissue underneath, it would be like blowing up a balloon (e.g. getting thinner). In fact, more than just the skin cells help cover the area. Blood vessels, connective tissue, the fat cells themselves all have to accommodate the increased tissue volume. As a corollary, when someone has massive weight loss, you can see the large amount of loose and excess skin. The signals from the body to make the skin cells divide to cover the larger area can't just reverse instantaneously (you also have issues with looser connective tissue, loss of elasticity of various components, etc.) so now you have large folds of skin hanging around. 

EDIT: Forgot to respond to your follow-up. You can have issues with less touch sensitivity but it's hard to say that it's just because of less nerve endings (your nerves can make new connections so you still have touch sensations). More often, losing feeling in really any part of your body (bodybuilders with massive skeletal muscles, areas of fat deposits) is a combination of factors like poor blood flow to the cells rather than just not enough nerve endings.