What would happen if the LED was connected the wrong way round?

If the LED was connected the wrong way, you would have bent some pins to have forced it to go in the socket the wrong way since it is designed to go in one way. Also, since you forced it and got it out of line, you may have broken the pins and may have a horrible time getting them out. You may need to take the unit into a shop and have someone that knows what they are doing fix it.

If the LED was connected the wrong way round it would not light. There are 3 ways of identifying which lead is which. The cathode is the shorter lead. The cathode has the bigger internal plate. The cathode is on the side of the package that has a flat (D).