you can not spike, toss or
you can not spike, toss or throw an opponent onto their head (and many, many more rules).
This only applies if it is a spiking impact that compresses their neck/spine. You can be slammed on the back of the head or face-first such as a Rampage slam or the Boetsch-chuck, respectively.
Doctors will halt the action to check on a cut and if it is hindering the fighter’s vision or breathing and the fight will be stopped.
I would add that they only stop it if there is excessive bleeding that they believe will continue to hinder breathin’ etc, and then only during a lapse in action.