"She FOLLOWED me and, causing a scene, told me I needed to put it on my face or leave."

This is a crime. Look up the law for harassment in your State. In mine it says--

It is unlawful for any one who “follows, monitors, or pursues another, whether in person or through any available technological or other means;” The key factor is provided under Subd. 2(4) when: “mental distress, mental suffering, or mental anguish as demonstrated by a victim's response to an act” occurs as a result of being wrongly denied their right due to their medical condition and then ordered to leave the store under the duress of the store manager calling the police.

You can cost the store lots of attorney fees without ever having to go to court. In fact, you don't want to go to court. In my 27 page Cease and Desist demand, I provided all the laws they were in violation of. Including OSHA regulations. I gave them 10 days to respond and offered to meet with them to resolve the issue. Their response costs them money and ties their time up costing them more money.