No, if it's injury edema would have happened right after or in a few days max, not 2 months later.
parasites are negative, you can trust that one, it's ether here or not, can't really miss it.
Feeding, supplementing - ok.

Okay, can you please take some more pictures, more clear ones, including underbelly and back legs. Please describe :
how long it is going on, how have you noticed? Is there any changes in edema over the duration of the problem, got bigger/smaller/same? Did anything else changed - behaviour, eating, pooping. Do you see that it influenced her in any way- harder to move?
The q you didnt answer - how often do you clean the tank? How often do you change the water, type of water?

You were saying she goes only in water bath, would you please describe how does it look like exactly - water? How long? Temp? How often? Does she goes on her own while in a bath or you massage her sides?

another question - can you try to feel her sides? Left? And right? Don't squish her much, but just try to feel inside, gently! What you feel, pls describe.

as of now I'm going with localized infection, possibly in digestive tract ( not pooping on her own very often lead to enlargement of the colon and consequitive infection, and vise versa, not pooping in her own often is related to anatomical structure of the colon, when it is enlarged). the location of the edema ( left side) is also suggesting that.
I doubt it's a renal problem. With any kidney or any other systemic problem edema is happening evenly on both sides, here we see very clearly differentiated left side, not so much the right one. Is it how it is? Or it just looks like it on the pics?