Hello dear and welcome to the medhelp forum. This wet or cool sensation in the knee is a part of paresthesiae, which could be secondary to many conditions. These are due to physical injury to the nerve like entrapped nerve or some direct pressure to the nerve or its spinal attachment. This sensation can also accompany diseases affecting nerves like neuropathy, diabetic neuropathy, alcoholism and herpes zoster. You need to consult a neurologist for a clinical evaluation and investigations like blood test including blood glucose profile, MRI spine to check for any disc degeneration or herniation causing nerve compression. Wish you all the best.
Thank you so very much.
I will call a doctor right away and thanks again
Vera