An operation in neck that affect spinal cord as a lesion , i feel hotness , coldness and sometimes numbness n my legs that transfer from up till my toes?

Neuropathy: I am not certain what our question is, but if it concerns possible neurological sequellae following surgery, then, yes, it is possible to have altered sensation following surgery on the spinal cord. You are experiencing paresthesias (altered sensation) and ought to discuss this with your surgeon.

Numbness: The cervical nerve roots innervate the upper body, the lumbar nerve roots innervate the lower extremity. Perhaps you have low back pathology.

Nerve issue: Your numbness can be due to abnormal nerve function due to nerve impingement or damage. Treatment varies depending on the cause of the problem. Have it evaluated and appropriately treated.