Welcome to the forum.
So the led is Red for the 11th flash?
If you see no liquid metal left in the slots, then the damage sounds like might not be the slot. But instead elsewhere on the board, due to the short.
If you haven’t heard of it, phase change thermal pads are a safer, easier alternative to liquid metal.
[Honeywell PTM7950 Phase Change Thermal Pads/Sheets] Application, Tips, and Results