Side-effects from hyperhidrosis treatments are uncommon.
The most common complaint is occasional mild bruising, which tends to settle over a week. Rarely, you may experience a slight increase in sweating elsewhere, but this is usually transient and settles over a few weeks. With the hands and feet, it is possible to experience mild muscle weakness, but this is uncommon and if it occurs, is temporary.
Some people find that they need a higher dose as the treatment may not completely achieve the desired outcome. This can easily be performed with a top-up treatment.