Creation,
The distal interphalangeal joints (DIPJ) are very susceptible to osteoarthritis. It may be some time before the changes start of affect the bones and thus show up on x-ray. Before that, the cartilage is beginning to degenerate. This can cause some swelling within the joint. Since it is such a small joint, it can't contain much swelling.
The pressure from the swelling, can cause ganglion cysts to occur. These are outpouching of the synovial lining from the joint. They are filled with synovial fluid (joint fluid). It looks like apple jelly actually.
In the DIPJ's these ganglions are called mucous cysts. They are very common. They usually show up on the dorsal aspect (top) of the DIPJ, usually, slightly to one side or the other. They can range from hard as a rock, to slightly bouncy (like a water balloon).
Sometimes the skin overlying the cyst can get very thin, and then a minor abrasion will cause it to rupture. If this occurs, or if the cysts are causing problems, such as pain or stiffness, then they are surgically removed. They can be aspirated (drained), but the cyst wall is still there, so it usually fills back up again.
If surgery is opted, the cyst and any small osteophytes (bone spurs) on the joint, are also debrided (removed).
If the little bumps are bothering you, you should see a hand surgeon for an evaluation.
Good luck.