I am not talking about body part hitpoints, but about hidden health stat which affects natural healing.
Remember: you are playing simulation game, not some modern FPS.
Disinfectants should only be used to treat bite (blue) wounds. Using disinfectant on infected (green) wound is useless and does nothing.
Also antibiotics is not some kind of panacea which heals you immediately - you should take them roughly twice per day and it can take several days to get rid of infection (depending on your health).