My mom has very bad short term memory. How do I convince her she needs help? Needs to see neurologist, but is very stubborn.

I'd immediately consult with an Elder Law attorney in the county where she lives. They should be able to do phone call or online consults. I'd have them review the documents you have to confirm what they say and what actions you can take now that are legal, regarding her care. You'll need to be able to intervene safely, but, keeping her from getting angry is probably going to be difficult. I'd try to have things in place for when that happens. You will need someone who is not long distanced, in order to intervene. You may need to retain the services of a professional for that if you can't be there. Covid makes all of this much more complicated.