The GP who saw Baby Peter a week before he died from sustained abuse says he should have examined the toddler more thoroughly on his last visit.
Dr Jerome Ikwueke has been giving evidence to the General Medical Council.
He faces allegations that he failed in his duty as a doctor to act in Peter Connelly's best interests.
Peter, from north London, died in August 2007 after sustained abuse.
The panel heard that Peter's mother rang the surgery on 25 July. Tracey Connelly wanted Dr Ikwueke to "get social services off my back".
Instead, Dr Ikwueke suggested she should bring Peter to the surgery.
The following day he saw Peter who had scabs and an infection on his head and fresh blood on his ear.
Dr Ikwueke told the hearing: "If I were to face the same situation now I would handle it very differently".
He said he did not undress Peter because he thought the infection on his head was making the child withdrawn.
Ms Connelly was due to take Peter to see a hospital specialist a few days later, and another appointment at the surgery was arranged for 2 August.
Dr Ikwueke accepted that with hindsight it was unwise to trust Ms Connelly, but said she had always kept appointments.
He saw her again without Peter on 30 July when she complained about being put under pressure from social services.
Dr Ikwueke said: "I have thought and agonised about it for days and months reflecting on what I could have done to prevent Baby Peter's death."
He told the panel he had since undertaken nine different courses connected to child protection.
He said the problem had been one of being excessively trusting and having a resistance to the idea that such horrible things could happen.
Dr Ikwueke was challenged by counsel for the GMC about his claim that he had spoken to a social worker after Peter's last visit to the surgery.
The panel was also told it was "nonsense" for Dr Ikwueke to claim he could not now recall the details of more than dozen visits by Peter to the surgery.
Peter's mother, her boyfriend Steven Barker and his brother Jason Owen were jailed last year for causing or allowing his death.
Dr Ikwueke is the second doctor to face GMC allegations over Peter's care.
Consultant paediatrician Sabah Al-Zayyat is accused of failing to spot that he was suffering abuse two days before his death.
She was due to face a GMC disciplinary panel in February but did not turn up.
The hearing was adjourned until a later date after she was said to be "suicidal".