I have heard that Canadian and European distributors are supplying low cost Botox to U.S. physicians? It is less expensive, about 40% less. What happens if a U.S. physician purchases the overseas product and then uses it on his/her patients? Is there danger and risk involved to the patient?

It is illegal to buy drugs from outside the U.S.  for use in the United States.  This is a safety issue for patients.

Many of these drugs are manufactured in India and China, where quality does NOT meet the FDA safety standards. 

There are real consequences of this ethically and legally in the US. The drug HAS to be FDA approved or the physician can loose his license and even be prosecuted for damages. This has been the case in a number of states already such as NY, CA, and FL. This actually protects the public from dangerous drugs and formulations and keeps the purity consistent.