I found an interesting article from 2003 which presents information from a study investigating the possible connection between muscial hallucinations and Lyme Disease. According to the article, two patients, both with persistent cases of the disease, had musical hallucinations after oral antibiotic treatment. However, the hallucinations stopped after IV antibiotic treament started, but resumed once the IV antibiotics stopped. Neither patient seemed to suffer from hearing impairment, which is often a cause of these kinds of hallucinations. However, one patient did have a lesion on an area of the brain typically associated with musical hallucinations, so this may have been the cause.
Doctors were unable to draw any definitive conclusions on the connection between lyme disease and musical hallucinations, but the cases provided interesting evidence.