Are Botox Results Permanent After Long-term Use?

This really depends on the patient and the concern targeted. It is true that repeated treatments can prolong results, but they may not be permanent and last just a few months longer.

Botox typically lasts for about 3-4 months but with regular appointments you can experience prolonged results so that you no longer have to have appointments scheduled as often as before. This is true for anywhere you have treated. 

Botox usually works for 3 to 4 months.  This depends on the dose, as well as the patient.  If the patient is hyper-metabolic, (i.e. in the gym twice a day) it may last a shorter period of time.  Likewise if a patient is very animated with the muscles of facial expression, this can also decrease the length of effectiveness.

Some will say that with continued use, the muscle will atrophy and one may use less Botox, or come in less frequently.  As of this writing, there are no good medical studies to show this.  Therefore we cannot say that Botox is permanent.

After repeated injections of  Botox, muscles can have disuse atrophy making them weaker. That will reduce the frequency of Botox injections but unlikely to be permanent.
In a way it is a blessing because any severe side effects or complications related to Botox will always be temporary.
Regards

To my knowledge, there are no widely accepted reports of this phenomenon. The muscles may weaken after repeated use but can return to normal after cessation of use.