Hi there, It sounds like there is some type of irritation or infection. You may have a small amount of movement (rubbing) between the implants and the skin. I doubt you are rejecting the titanium. They use this type of metal because it is the least likely to be rejected. When my son broke his ankle the Orthopedic Surgeon advised against NSAID's. He said it does help with inflammation but it slows the healing process of the bone somehow. He said to just take tylenol. If it doesn't get any better soon or you develop a fever or redness in the affected area seek medical attention. Elevation is good!!!Hope you heal quickly!!! :-)
I dont know about rejection but it could be the beginning of an infection. Have you been back to the doctor to let him see this? I believe most of them say "please call or come back if you have any problems". I think it might be time to call to make an appointment to see your doctor.