I've noticed that when I'm injured by clickers I roleplay the severity of the wound based mostly on the roleplay that caused it. Overrun by multiple clickers, and I'll act like I'm barely living, take a single arm hit, and I treat it less severely.
The problem is that the app doesn't know how strong the combat was; and I end up either underroleplaying excessively severe injuries, while I look like a malingering coward playing up minor injuries.
My suggestion this is some form of RP guide on the Medical Emergency screen. This could be as simple as a 1-10 ranking to something as extensive as "labored breathing, gaping wound, difficulty talking".
This of course wouldn't stop someone from stoically downplaying injury (or overplaying it). But it gives us an idea of how to accurately play the specifics.