Make Self-Care a limited use perk
Having self-care as an infinite use perk is very powerful on its own since it doesn't make you rely on your teammates or to scavenge for a med kit at any time. I feel like self-care should be one of the perks that should be used only if you really need to, similar to how Unbreakable only allows you do get up once, but still keeps the fast recovery rate. It shouldn't allow the survivor to be completely dependent without the aid of other survivors, and should only count on the perk when it's most needed, such as when there are no survivors able to assist you or when you're that last survivor in the trial.
I feel like the perk should either be token based or charge based. Having it token based can make it rely on helping teammates by completing altruistic actions, similar to WGLF and having a max stack of tokens. In turn, the perk could have moderately faster healing speed that current self-care, but fully healing yourself or having another survivor finish healing you when you're over 75% healed can consume a token, and you'll have to complete more altruistic actions to gain another token, and the survivor will start the match with either 1 or 0 tokens depending on the tier. Having it charge based would only let you heal for a certain amount of time and could be recharged by either healing teammates or collecting a med kit of rare quality or higher, making the perk not infinite but not very limited.
Let me know what other changes to the perk could be done to help actually balance it out. The goal is to not make the perk as crutch as it currently is and to not make it a staple perk for survivors for easier games. The game should be team-based and be centered around benefiting you for helping others and increasing the odds of survival instead of allowing survivors to lone-wolf the game by simply bringing in this perk. I feel like the game should be an actual challenge for the survivor instead of making it a huge challenge to the killer.