I am a germaphobe too but these days I worry more about squirrels getting COVID from people. Thousands of squirrels have been rescued by folks on the TSB, I can't think of a single case of anyone catching anything from a squirrel.
As long as there is recent rain or snow, water should not be in short supply so the water bowl is probably not needed. If you have a dry spell, maybe put out the water again.
Hopefully, the ivermectin will help and also with weather starting to get warmer, natural foods that are part of their diet will start appearing again. I just noticed that the tree in out front yard is starting to bud, hopefully this starts where you are too. Winter can be hard on smaller, fall babies but she has made it this far so maybe with your help, meds, and food she can hang in till spring comes along.
Do you have any rehabbers located near you?