Mom (93) always abused us. I ended up being quarantined now 3 months of caring for her 24/7. She's a true nightmare. Pls help.

Wear a mask when you're around her and areas she's in or been in recently to protect yourself.  If you've got no mask, use a bandana, scarf, whatever you can find or use.  If she complains about it, tell her you're protecting her from you.

Since you're in her home, try to ignore her complaining by changing the subject or leaving the room she's in.

If you can be in separate areas more, do that to give yourself space from each other, especially when she gets abusive like that.  Take a walk out on the patio? or somewhere in her home.  Make some You time, even if it's sit in your room and read, sleep, snack, an indulgence, whatever that will help you relax. 

She may be irritable, not feel well either.  Try to get her to eat and nap more, so you don't have to hear her complaining.

Does she need to be tested, x-rayed for coronavirus, especially at her age so she doesn't wind up in the hospital?  You may need to check with her dr. or yours or an urgent care or county health dept.

She can't live alone at 93, and you're at burn out; you've got to get some help for her (and you).  Maybe her dr. would refer some in home health care.  If her dr. will prescribe it, insurance likely pays it or some of it.  Otherwise, hopefully, she can afford to add some help so you can get a break. 

Start the ball rolling in that direction by talking to her dr. and her about making changes if you intend to continue to live there with and care for her.  Otherwise, you need to start shopping for assisted living at some level that works for her and that she can afford.

Sorry you're going through her abuse.

Jessica,
Can your mother afford helpers to give you a break, even if for a few hour or are friends willing to help? If there is not money available, I suggest call to the social worker at your local senior center to see if your mother qualifies for any entitlement programs to provide some in home helpers or your state senior services department.
I hope you are able to find some help to give you a break.

Jessica, your profile doesn't indicate that your mom (aged 72) has any cognitive or health issues. If this is true, why do you stay with her? Does she go out in public? If she hasn't had any contact with people and no one is coming into your home, what is the concern for being exposed? Maybe the best use of your time there is figuring out a permanent exit plan for yourself. The lockdown won't last forever. Do you have a job? Can you go live w/sibling until you find a permanent place to live? More info would be helpful. Also, many people on this forum who were raised by abusive parents will weigh in to tell you that you're not under any obligation to care for them. Let the county take guardianship over her and they will make all her care plans and decisions for her and your family will be relieved of this concern. I wish you clarity to see your options...and boundaries.

Jessica, are you stucks at mom's for the duration of the quarantine?

Do you have a place to go back to?