ok, this is the way it seems to me (basically i'm just parroting the stuff our kaplan instructor said)
panic disorder, agoraphobia and social phobia can be pretty similar--in all 3 situations you have people who are refusing to leave their houses. but:
panic disorder--the person is afraid of the actual trip...so if say the party was at their house and they didn't have to go anywhere they would do fine. also i think they don't have a fear of walking outside, just driving, flying, etc.
agoraphobia is a fear that you're not safe outside your home. this is what this woman seems to experience--it's not that she's afraid that everyone will criticize her because of her scar, she's afraid that something bad will happen to her when she leaves the house. so she doesn't leave it at all.
and social phobia is just fear of being in social situations. people with social phobia aren't all that afraid to go outside or take a trip in a car, they're afraid of attending social events or going somewhere where there are lots of strangers who might criticize them. so they're totally fine driving/walking around...they might go out and do their grocery shopping late at night, when there aren't that many people on the street.