Can botox in masseter muscle cause Marionette Lines?

Hi,I'm sorry to hear that you noticed marionette lines develop post masseter injection. Yes, this can happen if you had significant reduction in the jaw with Botox. The musculature that was supporting the skin is now smaller, therefore there is increased skin bunching that can occur around the marrionettes/jowl.Since we don't have a photo or injection location information it will be hard to say for sure. If it was caused by Botox then it is sure to subside once the medication wears off.

Its best to provide a before and after photo to compare, its not likely Botox caused marionette lines but if indeed it did, it should resolve once the effects of Botox wears off

Since there are no pictures posted, it is difficult to respond specifically to your question. However, any time there is a decrease in subcutaneous volume, the skin will sag and possible creating folds at attachment junctions such as nasolabial folds and marionette lines. This is seen when we lose midface fat volume. In your case, its possible (although unlikely) that the atrophy of the masseter muscle after Botox injection (unlikely after one injection 2 months ago) created sufficient decrease in facial volume that the skin envelope excess created a temporary fold at the cheek-chin junction. If that is the case, then I expect a return to pre-treatment state in 3-6 months when the Botox is completely worn off.