How long does it take for a bruse under the big toe nail take to heal?

It varies: The resolution of a bruise under the toenail is dependent on many factors, i.e. Circulation, skin or nail integrity or disease, environment, shoes, continued pressure, etc. If the color, quality, sensation or size increases you should see a podiatrist to be sure of the diagnosis.

Can take : Up to a year for the big toe nail to grow out fully. Have you had bruise checked? If not, do so.