I have arthritis in my hands i notice a bump on my right hand under my skin at the knuckle joint under my middle finger is it osteophytes?

Doubt osteophyte: Typically osteophytes come from osteo "wear and tear" arthritis or arise years after trauma, like from a broken bone poorly healed. As a general rule folks under thiry should not have osteoarthritis. Finger pain and a lump at a 3rd knuckle could be another form of arthritis. Blood tests and x rays seem like a place to start. Other causes of hand lumps also exist. See your provider.