Try different ways of holding the VisaBoost in order to find the right angle of the treatment - the probe needs to completely contact your skin. Make sure to move the VisaBoost slowly.
In areas where full skin contact is harder to achieve, such as the forehead, try different ways of holding the appliance. Try vertical and horizontal movements to find the best way to establish proper contact with your skin.
You can also hold your hand still and move your head instead.