Hello, Ideally a correctly inserted Implanon (contraceptive implant) does not form ripples or feels lumpy. A correctly inserted implant should be clearly palpable by you. Both ends should be clearly felt between the thumb and finger. Since you can t feel the implant properly, it is feeling lumpy and is forming ripples contact the healthcare provider to confirm that it is not broken or has become bent while in your arm. In the meantime, use other birth control methods (like condoms) for protection. Get it assessed and replaced if need be so at the earliest. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Nupur K., General & Family Physician