I used my hand to brace a fall. didn't feel much pain at the time. later i saw a small raised circular area of blood (3/16" diameter) on inside of thumb/hand joint area. i feel some thumb pain gripping something strongly. what to do? is this serious?

The many tiny bones of the hand are highly susceptible to fracture during a fall. Ignoring such a fracture may lead to arthritis later in life. Since you didn’t go to an ER immediately after the fall, you should schedule a visit with your doctor asap for exam and X-ray. You may also need to follow up with an orthopedic hand specialist. If you can’t get a visit soon, go to urgent care.