Hello, It would be great if you would have mentioned your son s age as the medicine is not advisable in children below 7 years of age. Regarding hallucinations, there is possibility that the drug is causing this but to be sure, a psychiatric consultation is advisable. A dental infection does not cause hallucinations. Get the infection examined from a dentist as soon as possible.Painkillers like paracetamol, appropriate dosage as per his age will be helpful in reducing the pain. Along with that antibiotic treatment is necessary so seek medical help from a dentist soon. Take care. Hope I have answered your question. Let me know if I can assist you further. Regards, Dr. Manisha Auradkar, General & Family Physician