I am experiencing a cold and wet sensation in my left calf. have also been experiencing pain in back of knee. foot bone issues as well. why the cold?

Sensations vary: If there is swelling not related to infection, it can reduce blood supply to the area and blood keeps the temp up to normal - when it's less, the area gets cooler. Massage or rubbing gently can sometimes bring blood in to warm it up. See a Dr for physical therapy referral and Rx devices if possible. Problems of this sort can influence other systems and are worth treating!