From what I understand, most side effects are mild and temporary, but there can be some unusual reactions in rare cases. The most common ones like slight bruising or temporary headache usually resolve within a few days. Less common but possible side effects might include temporary weakness in adjacent muscles or slight asymmetry if the injections weren't perfectly placed. I've read about cases where people experienced mild flu-like symptoms or upper respiratory infection symptoms coinciding with their treatment, though whether this is directly related is debatable. The key is having realistic expectations and choosing a practitioner with strong qualifications and experience. If you do experience something unexpected, your practitioner should be responsive and able to address your concerns.