92 is getting on the high side. 86 is as high as they ever need it.
Sometimes babies just die. The spot was his gall bladder and is common to see on babies.
Chances are it was just one of those things, especially if you have others you keep the same way that are fine. I would lower your high end heat though.
But I don't understand how an almost year old, seemingly healthy baby can just die. And why his mouth would be bloody.
1 Ultramel Stripe Corn: Pyro
1 Normal Corn: Hypno
1 Normal Ball Python: Bubba
1 Spider Ball Python: Spiderman
1 Red Tail Boa: Zero
3 Bearded Dragons: Tweak, Puff, and Kimbo
2 Leopard Geckos: Gizmo and Geek
3 African Fat Tail Geckos: Oreo, Comet, and Jaws
2 Green Iguanas: Rex and Frogger
1 Fat Rat (Not food): Marshmellow
3 Red Eared Sliders: Donatello, Michealangelo, Raphael