Foot numbness is not always dangerous or a sign of anything bad and sometimes your feet can become numb just because the blood flow has become restricted or you have pinched a nerve in your foot.
However if the foot numbness continues constantly then it can be a sign of diabetes or Peripheral neuropathy which is caused by damage to your peripheral nerves.
If the foot numbness continues or comes back often then I would tell a doctor about the foot numbness so they can make sure it's nothing more serious.
But sometimes the foot numbness especially if it constantly happens can be a sign of diabetes because foot numbness does sometimes occur with diabetes.