A hard bump on a finger joint can be caused by a variety of reasons, and is not a single disease. If the lump is painful when pressed and grows slowly, affecting the movement of the finger joints, it should be considered a tendon sheath cyst, which is mainly related to injury or chronic strain, such as long-term typing can cause chronic injury to the finger joints, making it easy to develop tendon sheath cysts in the finger joints. Tendon sheath cysts can be destroyed by squeezing the cysts hard and then bandaging them with pressure, but this treatment is likely to cause recurrence. If recurrence is frequent, surgery can be performed if necessary. If the hard bump is not painful and occasionally has pressure pain and bleeds easily after friction or impact, the condition is likely to be a wart caused by a toxic infection. It needs to be diagnosed by a dermatologist and treated with methods such as laser or electrocautery therapy. If necessary, surgical removal can be considered. If you’re looking for a way to get the most out of your finger joints, you’ll need to get a rheumatoid series of tests to make a clear diagnosis before you can do targeted treatment. In conclusion, it is best to go to the hospital to have this hard bump on your finger joints checked out and get a clear diagnosis before doing targeted treatment.