Hi!
Since the bulge comes only after using the elliptical machine and subsides after some time, please do not use this machine until you have consulted an orthopedic specialist. This bulge can be due to pre-patellar bursitis (inflammation of a bursa that lies above the knee cap), or patellar tendonitis due to inflammation of tendons inserted on it). The usual treatment is rest, ice application and anti-inflammatory drugs. However, a correct diagnosis is important. So please consult a specialist. Take care!
The medical advice given should not be considered a substitute for medical care provided by a doctor who can examine you. The advice may not be completely correct for you as the doctor cannot examine you and does not know your complete medical history. Hence this reply to your post should only be considered as a guiding line and you must consult your doctor at the earliest for your medical problem.
Thank you very much. I will see a doctor about it as soon as possible. Jim