Every time you receive damage, both physical and psychological, it does not harm you, in fact it benefits you, gaining resistance to that damage or making you stronger.
For example, if you are burned, you will gain a body of fire that will allow you to burn your enemies.
If they cut you, you can be immune to deep cuts, if they blow your head off, you can blow the heads of others.
If you drown, you can breathe underwater.
and many other things, whatever harms you, you would simply benefit from it.
