LPG is very dangerous in a lot of ways, from frost bite to massive explosions, I would suggest taking an educational course before attempting repairs you are not trained for, and never attempt repairs you have not been thoroughly trained to complete safely.
That said, where ever LPG expands from a liquid to a gas, there is an absorption of heat from the surrounding area,
You may well have a leak of LPG gas, or other form of expansion from liquid to gas.
Remove the tank and shut off the flow of explosive fuel before any other actions.