Not so far. There are no cell towers or relay stations on Mars.

If the photo cell was on during the short circuit then the chances of damage to the photo cell are at a minimum. If the short circuit occurred when the photo cell was operated then yes damage to the internal contacts of the photo cell could have happened. What happens is, the short circuit is downstream from the photo cell and when the contacts of the relay close in the photo cell the dead short is applied to the contact faces of the relay. This is somewhat like striking an arc with a welded with the same results, the contact faces weld close and the circuits breaker trips to open the short circuit. With the pole faces of the photo cell's relay closed it gives the illusion that the photo cell is not operating. The photo cell's circuitry will be working but the relay will not drop the circuit open because of the welded contact in the relay.

Neurotransmitters are chemicals that send messages from one cell to another.

By covering the photo cell and if the relay coil doesnt work.

By releasing chemicals (neurotransmitters) @ the synapse to the next cell.