Lexi,

As someone who cut herself and is still getting over all self harming behaviors, here's my two cents.
Your friend needs ALL the help and support you can give her right now. Give her the benefit of the doubt and assume that she's forgiven you so fast (for doing the noble and RIGHT thing, kudos to you!) because she knows that you have done right and because she NEEDS you.

As for your sociophobia (been there too), could you get counselling? It's helpful to talk over and analyze your feelings -- maybe there's a hidden reason why you're not comfortable in crowds and you can overcome that with some help.

Oh, and if you need to write how you feel, I'd suggest doing it on paper next time. Ink poisoning is not cool.