New Foster Dog

I want to put my main question first and then the details below. how can we get her to be comfortable with touching or even if we should try at all.

we’ve been fostering this sweet little girl for about a month and a half now. all we really know is she is around 10, came from a hoarding situation, and had such horrible fleas she lost all her hair on her tail and rear. this ‘issue’ we’re having is that she absolutely hates being touched. (i say ‘issue’ but it’s really not a problem whatsoever, she may just be like that. i just don’t know the right word for it). she doesn’t flinch ever but will run away and cower whenever you try to pet her. we’ve gotten her to take treats from our fingers but she won’t take it from our palm, she’ll sniff but then back away real quick afterwards. her hair has grown back so much and she rarely ever itches anymore. i just found out that she doesn’t mind the pets if it over a blanket that covers her. we want to be able to take her to the vet but it stresses her out so much to be picked up we can’t even get her in the car. and advice or help or thoughts would be super helpful!