Thanks for writing in.
Exercising causes sweating, this leads to cooling of the skin surface. There is also lot of energy consumption which can lead to depletion of sugar and electrolytes. It is important that you take warm up exercises before doing intense workout. You should also keep yourself hydrated. Shivering occurs in many people after heavy exercising. If you have family history of diabetes
please et screening tests done. For your skin, please consult a dermatologist
who might be able to prescribe medication, but it can take a while for changes to show up.
Hope this helps