My mom is in a rehabilitation setting for Edema in her legs. I expressed valid concerns regarding known retaliation against my mom, what can I do?

What is staff retaliating against, OP? Your interference? If you don't approve of this facility, get mom moved to another one. Time is very limited in rehab, as you know, so you'd be better off moving her than trying to fight the system and see results, imo.

How do you know nurses are bullying staff?

There is a chain of command in facilities. The aides report to the LPN, the LPN reports to the RN and the RN to the DON ( Director of Nursing). The DON is who you could talk to.

Is your Mom not getting her wound care by a Woundcare Nurse? Is Mom OK otherwise. Maybe she could get in home care for her wound. Maybe you need to find another Rehab. My daughter was Unit Manager for outpatient woundcare. Could Mom do that?

From the internet:
"The following organizations oversee rehabilitation centers
1) Rehabilitation Services Administration
2) Healthcare Facilities Accreditation Program
3) The Joint Commission (JCAHO)
4) Commission on Accreditation of Rehabilitation Facilities
5) Council on Rehabilitation Education"

Sounds like you will be quite busy looking them all up, doesn't it?
My own recommendation would be the JCAHO as they often are involved most solidly in licensing, at least in my own state.

Do know to have all the SOLID proof of your accusations at hand for their perusal.
Good luck.