Hi sleepyhead,
Welcome to the forum.
I can't advice you on BDD as I have OCD I just wanted to make sure that you didn't have to wait for a reply.
What I can tell you is that I had terrible acne on my face, chest and back as a teenager and felt like you that I was ugly. Like you I wasn't ugly I just had a mass of spots. They all went eventually after seeking help from my GP and in those days there wasn't much choice of medication to use unlike today.
If you don't eat properly you're not feeding your skin and giving it a chance to heal itself. Without adequate food and the correct food at that, it can't renew and heal itself. It's like asking a builder to build a brick wall and not giving him the mortar to hold the bricks together
If you are using a concealer are you using one that wont block the pores on your skin further. There are products on the market designed to help problem skin and you don't have to pay a lot for a good product. Some of the supermarket skin products are excellent speaking from experience and they are also cheap - important when you're a student
Self harming will certainly not help the way you feel and so you should make an appointment to see your GP and ask for help. Don't hide anything from the GP tell him/her everything. Tell him that you need help with your spots, but also that you are having problems and are self harming and can he refer you for help. Remember if they don't know about the problem they can't help.
The BDD forum can be quiet but you need to talk to people and not feel that you are alone as you're not. So you can always join in on the main OCD forum members from all the different forums often use the OCD forum and there are lots of students on it. We're a friendly bunch and will be there for you.
So first stop GP and remember you don't have to be alone.
Look forward to hearing from you.
Trudy