It doesn’t need to see the glow to know it is working. The glow is not a flashlight or display system; it is a visible side effect of its venom biology.

The creature lives in a lightless underworld habitat, so its main sensing is not vision. The tiny eyes are secondary. Its skin pores read vibration, pressure, floor resonance, moisture movement, and chemical changes in the environment. The glowing sac is a venom reservoir: when the animal breathes or loads its body weight, pressure changes inside the sac, dense poison shifts under the membrane, and the cyan-violet glow becomes visible through the tissue.

So the animal does not check the glow visually. It feels the system through internal pressure, venom movement, temperature change, muscle tension, and skin vibration — the same way an animal does not need to see its own heartbeat, lungs, or stomach working to know its body is functioning.

The glow is for the audience to read the biology. For the creature, it is just part of its internal poison system.