I banged my thumb very hard. It has swelled up and the nail is dark blue. It keeps throbbing. What should I do?

In this situation, it is best to alleviate the pain with over-the-counter pain medication such as Tylenol or Advil. Applying ice to the injured thumb can also help reduce swelling for the first 2 to 3 days. If the nail needs to fall off, it will do so on its own regardless of any intervention.