Can Facial Muscles Become Weaker After Botox?

Annabella, the reason that you do not have to worry is that the Botox browlift relaxes those muscles that pull downward on the brow. Relaxing those muscled repeatedly over time may cause them to weaken, but this just means that a Botox Browlift works even better and lasts longer.
The injections do not affect the muscles that pull upward and therefore if anything, you will may have slight upward movement in the brow if you stop using Botox, at least until the muscles that were injected recover to their original state.

Whilst we encourage patients to wait as long as possible before getting Botox, if you have static lines you may be a good candidate for Botox. Botox is a very safe treatment, and very mild muscular atrophy can occur with prolonged use of Botox, but this is extremely rare and the effects are minimal. You can also help counteract this effect by encouraging collagen production through Micropen treatments which keep your skin firm and plump. Any side effects are temporary and will gradually wear off with the Botox after 4-6 months. Perhaps the greatest risk when taking into account your age is the cost, since if you like the temporary results then you may want to continue having the treatment. 

Hi Annabella,
Not to worry. Studies have shown that in patients who have had repeated treatments over years that the lifting effects persist not to mention improvement in skin tone and texture. Just choose your physician carefully, someone with experience and who knows what they are doing. In Chicago you are fortunate to have many skilled physicians who get great results with Botox.
Good luck and be well.
Dr. P

Annabella, This is a good question and an area of great contention. Botox does cause a temporary paralysis of the muscles injected. However, it wears off over a period of 3 to 6 months. With long-term use of Botox in patients, I have noticed very little, if any, clinically appreciable atrophy of the muscles. Certainly if you have never done Botox, trying it to see if you like the effect will cause no atrophy. Progressive brow ptosis (falling) after Botox use may be attributed to inappropriate Botox injections or just to the normal aging process. Botox does not stop the aging clock, it just pauses it for 3 to 6 months.
Good luck with your Botox. I hope you find this helpful.

While long term treatment can cause some muscle atrophy, the effect will not cause your result to reverse to a more heavy position that prior to treatment. In fact quite the opposite. It may increase the duration of the "brow lift" until the muscle strength completely returns.