I have a bunion on my foot. my big toe on the same foot has been numb for a few days. what could be causing the numbness?

Risk of damage: It is not easy to determine why your toe may be numb, from the information provided. However a numb toe could lead to unrecognized injury and infection. You need to be checked for nerve damage and diabetes.

Nerve irritation: There is a nerve that runs over the top outside part of the big toe joint. It can stretched over the bump of the bunion and shoes that put pressure on that spot can make the toe get numb. Usually wearing wide toes shoes for a whole or no shoes will help it recover.

Few things: Local nerve irritation, anterior tarsal tunnel syndrome, possible back problem, possible sign of a systemic disease. I would see a podiatrist to help differentiate.