I think it's edema as well. Which means you need to find a vet immediately. To avoid this happening again your res needs to be kept in the proper conditions. She needs a big tank with a filter. She also needs a basking area with a uvb light and a heat emitting light over the basking area. She will also need a heater for the water. Here is a link for basic res care. Please get her to a vet quickly.
http://www.redearslider.com/index_basic_care.html

