Botox is generally very safe. However, the official Botox website lists "dry mouth" first under the section of "Other side effects..." There are some anecdotal reports that up to 1% of Botox patients experience some degree of dry mouth. If your dry mouth persists past a few days or a week, you may want to see your primary care doctor for treatment options. The dry mouth, if due to Botox, should not at all be a permanent problem. Although, it may take weeks or months for your symptoms to fully resolve. It would also be a good idea to report your symptoms to your treating physician. It is unlikely your dry mouth symptoms resulted from Juvederm. That filler is made from hyaluronic acid which is rather chemically non reactive in the injectable form. Best wishes to you.