A micrometeorite (including space debris in LEO) hitting the metal wall of the ISS would likely cause a shower of secondary high speed fragments. But there are other "softer" materials proposed which would just let the object through without much interaction. For example by Bigalow Aerospace.
What would happen to a human who is hit by a micrometeorite directly? Take a 1 mm diameter metal object at 30 km/s impact speed as an example. Much smaller but much faster than a bullet from a gun. Would it just make a thin hole through the body, or would it like most military bullets tumble and tear up a much larger cavity in the tissue? Does it matter much how fast the projectile is spinning?
To my knowledge, micrometeorites have never caused any actual injury or even any important damage to equipment, although it is a much talked about potential threat.