Hi welcome to Health care magic forum. You had a swelling of a silver coin size,below the elbow, with out pain but is tender. After 3 days also no change, means there is some structural change in the tissues, and you should see a doctor for diagnosis and treatment. It may not desolve by its own. I could be a lymph
gland secondary to some infection distal to that swelling.
You may have to undergo MRI
besides other routine tests for confarmation.
Besides i advise you some diet recommendations as aviod taking potato, other tubers, pulses, and fish, as these tend to increase the swelling.
Take more of green leafy vegetables, sprouts, milk, egg, meat, sea foods other than fish, chicken, fruits, juices, and dry fruits. which increases blood vital to all physical activities, resistance to all infections, and stamina to all works to be done, and to bear the pains of the disease.Wishing for a quick recovery and thanks for calling.