If you are having lots of rain and the leaves are turning transparent, then it is likely the plant is rotting. Please post a pic right away.
If it is rot, it spreads rapidly and can kill the whole plant. A whole plant can rot within a day or two.
Emerald Giant is susceptible to rot. I grow them and they are generally an easy semp, but don't like to be disturbed much when wet. I myself have lost plants of Emerald Giant to rot. They can get very large, over 8 inches.
Generally the cure for rot is to dry the plant out immediately. This can involve digging it up and putting it some place where it will get air flow and no more moisture. I am reluctant to tell you to do that until I see a pic, but digging and drying a healthy semp should not hurt it if you are gentle.
Do what you can to protect from more rain. If you cannot get a pic right away, you may want to consider digging it up, moving it to a protected spot (leaving it out of the ground for a few days) and drying it.
