What part of the hand is affected? Please be as detailed as possible
Is there any colour change, temperature change or swelling?
How long has it been a problem?
If the entire hand is hurting then you may have a problem higher up such as with the neck or shoulder. There are three nerves which are involved in hand sensation and movement, but from your description then we cannot say that just one is involved so that would require examination of the neck and shoulder area.
You do not mention any change in color or temperature so it is unlikely to be a circulation issue however than cannot be ruled out until your peripheral pulses at ulnar and radial arteries are examined.
So you need to see your family doctor who may want to send you onto a consultant depending on the results of examination. They may want to try some medication which blocks nerve impulses to see if that improves your symptoms.
In the meantime all you can do is painkillers such as tylenol and if you have any shoulder or neck pain then use heat pads in this area (not the hands).
Try to keep your hands active today to encourage full circulation and muscle use but so be careful with heat and sharp objects if the numbnes continues.
Any colour change today would require visit to ER.
Does this help?