I don't think Liz didn't like you at all. I think she probably, felt quite honored that you looked up to her, thought that she was beautiful, admired her and wanted to be like her, what girl would not like that?
I think you spent too hard trying to befriend her and she has her own group of friends you know? I mean, you only befriend people that you feel you have connection with and she just didn't have that connection with you.
She didn't ignore you at the mall? She didn't remember you. I mean that was 3 years ago, you meet so many people in life don't you? I mean look at the jobs you were/are doing, how many people do you meet every, single day?
Your mind is playing tricks with you, re-read the above... And once you accept that, you will realise "oh", that's true I only accept people that I want to be friends with, like not that creep that tried to be friends with me, that makes sense ....
Cutting is stupid. I hope you've out-grown that side... Out of all the girls that I know that used to cut, none of them do anymore.. They grew stronger and realised how good a person they actually were and went on to make friends and boyfriends finally and are really happy in their lives. Time for you to shake yourself and realise the same.