Check if there is any loss of sensation of the affected hand (like differentiating between hot and cold water), also check if there is pain, if present is it present throughout the day or is it intermittent (if the pain comes and goes), check if the tremors (trembling of fingers) are present continuously or is it present occasionally. If you have ruled out all the conditions mentioned then it might just be because of weakness of the nerves.

identify the cause as discussed and avoid the same. Have a balanced diet rich in proteins and macro nutrients like dry fruits, banana, peanuts, sprouts, curd... Get a thyroid profile done and check for any abnormal values. Lastly if the symptoms are still not relieved lastly get an arterial doppler of the upper limb to rule out Raynaud's disease/ Burger's disease (block of the artery of the upper limb/hand)