I would say your body core temperature control has improved, not worsened. I was the same before my heart attacks, I would work in the building trade all day out in the blazing sun and not produce a drop of sweat. However, I would feel nauseous and get headaches after a while. Now in the sun I do sweat a lot more and get no headaches or nausea. I used to really feel the cold weather, shivering all the time. I had to wrap up like an eskimo but now I can still feel warm when most other people are wearing thick coats.
Maybe when your circulation improves, the heart can handle rerouting blood for cooling or warming more easily?
At cardiac rehab, I used to sweat like mad, but the medical staff all said that was a great thing and definitely nothing to be worried about.