@OokawaAlright I took way too long to get to this. Anywhoozies good rolls!
You pass the constitution check, so while the trog's corpse is still foul and disgusting, you manage to keep your guts in check and aren't sickened. You proceed to check the corpse.
With a natural 20 for a total of 22, you definitely know that this trog was killed with a long broad blade, likely a two-handed weapon of some sort based off the angle of the cut. You also know that this decapitation was it's only injury so whatever killed it managed to kill it in a single blow. Based off the stiffness and warmth of the body, it's only been dead for about one hour. Whoever or whatever killed it must be very close. Finally you can tell that this trog is both male had sex fairly recently. I'll leave it to you how you come to discern this, but it is important for one major factor: female trogs are extremely rare and often very powerful (Aka actually intelligent), and often serve as queens of sorts. Which means that this trog likely comes from a larger brood instead of simply a roaming band. This is important for two reasons: one that likely means that whatever band this trog was with isn't just hunting to sustain itself but also hunting for his brood, and two that brood will likely have various treasures and loot from dead adventurers or simply scavenged as the trog queen demanded.
Well granted the last bit is just something your character could safely infer based mainly one what little she may know of trogs. They're basically subhuman goblins. Breed en masses to fight en masses, hordes shiny things, kills anyone they can catch. Typical stuff.