"Speed bumps", or sores from stimulants are caused by the rise in body temperature. Do you have the urge to scrape/pick at them? That can also happen. Despite all the theories in science that people "need" these drugs and they are "safe" as long as a doctor gives them to you doesn't change the fact that it is what it is: a stimulant, amphetamine, speed, a toxic drug that causes many health problems.

And yes, very hard on the cardiovascular, I would be concerned with that if I had risk factors.