Hi doctor, I jammed my little finger about a month back, I am still having the blood clot in the nail. What should I do? Just leave it to grow?

Yes. What you describe is a black fingernail or subungal hematoma. This can be extremely painful when it happens and there can be pressure under the nail from continued bleeding. Most of the time the pain and throbbing improves with rest & ice. The discoloration improves with time as the blood stained nail grows out. If there is no pain leave it alone. The clot will clear with growth of the nail.