Shrogs don't sweat, do they? If so, they might dissipate heat by panting or through their nasal passages, like dogs. If these live someplace that's always cool, and possibly don't seriously heat themselves up by sustained and strenuous physical activity, then the usefulness of a short snout for cooling down would be reduced. Perhaps, if it lives in one the many suggested "grand canyons", the perpetual shade would give it cooler than expected temperatures in warmer climates. Alternatively, you could have it dissipate heat in other ways, reducing the usefulness of the mouth's surface or nasal passages.
You could say it has a lengthened pharyngeal region, which conditions the air instead of the nasal passages. (I used
speculation on humans as a basis.)
Are you giving it a short head and then explaining how it can survive, or giving it a short head, finding a compelling reason for it to gain one, and then explaining how it survives within that niche? Understanding the "reason" for its very short face could help. Is it "degeneration" from lack of need or adaptation to something that encourages a very short snout?
If its snout is shorter because it eats soft foods or cooked foods (perhaps by stealing from Taserflames, benefiting from cooked corpses, or "cooking" on the warm embers of their fire-pits), then you could use information from hypotheses on humans' shorter snouts relative to the closest living relatives. If its feeding style depends on placing its face very close to its foodstuff, you could use walrus or marine iguana skulls as a basis.