Its going to depend on the type of story your trying to write.
If its a power fantasy then you have more leeway then if its a grimdark setting for example.
What matters is what your trying to write.
I didn't.
Of the MC's who fight consistently and get hurt in my stories none of them have the ability to self heal inside the battle itself. Its part of the fight tension and skill test for the MC's to get through these fights without the ability to shrug off wounds etc.
I have had some who...
It really depends on your setting.
I think this would be a great way to include something that is antiemetic. Aka knowledge that actively tries to make you forget it.
For someone who never forgets suddenly finding there is a gap in your memory will would be...traumatic. And you can spin that...