Kelly: people have eyes... they see what goes on... EVEN IF they don't see everything, they have already formed their own opinions. What does it matter what they think - or if your mom can persuade them of bald-faced lies?
Your mom - like my mom - is NOT a normal person, is not rational - and appears not CAPABLE of rational thought & normal feelings. These people don't change, don't have epiphanies, don't realize what they do to other people. Many of those employees already have her pegged - but don't feel able to challenge her; don't have enough personal power being dependent on her for their own paycheck. They already know your side - some have probably already seen enough through their own interactions with her.
Do you have to tolerate it because she's your mom? Not one bit.
Draw your boundary in concrete (not sand) and stand proudly on your side of it: no doubt, no remorse or wishing things were different.... no secret hope that "someday" "something" will happen to make things the way you hope-want them to be (normal).
There is no truth to your mom's not-so-subtle implication, that you'll have to "come crawling back". Other people will see your strengths, your experience, your skills - for what they ARE... not for the faulty judgement of your mom. You need not fear that others will see you as she does... or treat you as she does... because not that many people are LIKE her, this way.