Perk for a maniac.
The bottom line is, a wounded survivor will not be able to completely recover on his own, and in any case, he will need the help of another survivor. (Except for the syringe, adrenaline, and other perks that can completely heal you at a time. The doctor himself - cannot completely heal)
For example, after the survivor independently cured for 80%, his self-healing ability is disabled. And the survivor is forced to resort to the help of another survivor
If the perk is too strong, then you can do a cooldown for a while. So that a stroke that cannot be cured on its own, fires every N seconds