Pain After Dental Implant Surgery

Michael, a dentist, asks:

I have placed 6 mandibular dental implants last week in a middle aged woman who has adequate bone height and width. The left side of is asymptomatic and healing well. The right side is extremely painful.Â

After the anesthesia wore off she immediately began to have pain on her
right side. After 3 days the pain was still severe and I opened the
flap and cleaned the site and irrigated with 3% hydrogen peroxide to
kill the anaerobic bacteria that I presumed were causing the infection
and inflammation.

One day later, her pain decreased and she told me
that it was the first night that she could sleep without pain. But she
said me that she began to feel a little tingling and throbbing on the
left side of her chin. The throbbing and aching is still going on after
8 days. I have prescribed systemic antibiotics and analgesics and she
reports that the situation has been improving but has not been completely
resolved.

When I look at the panoramic radiography I can clearly see that I am not into the inferior alveolar nerve or mental nerve. What do you think has caused this problem? Have I done something wrong? What can I do now to help this patient?