When Injecting Botox for Forehead Wrinkles, What Are the Chances of the Botox Travelling to the Lungs?

While there is a risk of migration, I haven't heard of Botox migrating from the upper face to the lungs. It is highly unlikely.

Botox is a medicine that is injected into the specific muscle.  It is designed not to "travel" anywhere.  As of this writing, I do not know of any case of forehead or crows feet  injection of cosmetic Botox effecting the lungs.

Botox injected in cosmetic doses poses no risk to systemic spread. Botox as a drug does not cause pneumonia. See a reputable Doctor in your area who can explain the possible complications

The chances of this happening are extraordinarily rare, less than 0.1%.  Botox is derived from Botulinum Toxin Type A. Allergan states that a potential side effect of Botox is having the toxin spread away from the injection site and through the body.  This is extremely rare when a treatment with Botox is performed properly. When Botox is administered for cosmetic purposes, it is specifically injected in a given area to address the muscles causing wrinkles.   Botox has been FDA approved to treat certain issues. When it is used properly by a trained physician for these approved purposes, you really have nothing to worry about.  Any side effects experienced are associated with the injection site, and may include the following:

1) Slight bruising
2) Swelling
3) Temporary ptosis (drooping of the eyelid)
4) Allergic reaction at the injection site
5) Muscle stiffness near the injection site
6) Headache

Thanks and I hope this helps!

When injected properly in the forehead, Botox is not likely to be injected intravenously for it to cause paralysis of the diaphragm, affecting breathing.