Those are call fireflies.
There is a cool addition to cycles render where you can add a denoiser to the compositer (it’s working in blender 2.82a I know for sure). You just enable the “use nodes” one the compositer workspace and then add a DeNoise node after the render and then connect that to the output. It will remove your fireflies if you just want a quick and dirty.
The new lighting course by@jlampel is probably worth looking into as well.
