What to do if i banged my toe hard and the nail has gone purple..?

No worries: Happened to me 8 months ago. The nail is attached to the nail bed. When injury occurs, the union between the two gets disrupted and bleeding occurs under the nail. Eventually it will fall off and a new nail will grow in. this process takes about 8-10 months. Mine is almost grown back. No pain....no worries. If it gets red, swollen or hurts, see a Podiatrist.