For all those people telling her to live with it, or just get over it, do you think she would be posting here if she hadn't already tried that? Right, rant over.
I'm sorry to hear that you're feeling this way. I felt exactly the same as you. I was teased for years about my nose (far too long, bulbous tip, deviated septum) to the extent that I developed depression, and didn't want to leave the house or go to social events. There are people posting on here who also don't like their nose, but say that they still get on with their life. That's great for them. The human mind is a bonkers thing, and people react differently to everything. So these people can't apply 'what works for them' or 'just get over it' to your scenario. Equally, I can't apply mine, but I thought I'd tell you about mine so you had someone backing you up.
When I was 18, and about to head to university, my hate for my nose became so bad that I genuinely considered not going to university. I couldn't bear the idea of being in social events, and had no self confidence. My parents could not afford to pay for surgery, and unfortunately the NHS really are very picky about offering rhinoplasty unless it is for medical reasons. Which, I actually do believe is fair enough. The whole, woman getting breast jobs for cosmetic reasons on the NHS, seems crazy to me, but I don't think there are actually that many cases of it happening. The media tends to blow things out of proportion.
As a student, I couldn't get a medical loan. However, I managed to persuade my parents to take out the financial payment spreading thing. (Sorry, it's got a proper name, and I will check for you!) Basically, you go private, and instead of paying the (roughly £3000 - £4500) for the surgery upfront, you agree to pay back a certain amount each month. Some private companies will charge interest on this, others won't (or will charge a lot less) so make sure you look around carefully. It had to be in my parents name because I was a student, and had very limited credit history. BUT, I paid my parents the money each month, so they didn't have to pay anything.
So, I had the surgery. Then paid my parents £300 each month. This is a lot of money. But I was so desperate by this point, and there was nothing else I wanted to spend money on more than the operation. I worked hard for the money, in a part time job. It did take almost two years to pay all the money back, but I'm so glad I did.
So, I know your parents say they don't want to be involved, but if it really is affecting you this badly, then maybe you should suggest this to them? They won't have to pay anything, and presumably they trust you to give them the money.
Another thing I want to add (and again it might not be the same for everyone) having the surgery did not completely change my life. Or my nose. You have to be realistic about the outcome. Don't forget you have an underlying bone structure that can only be changed so much. Also, people seem not to realise that after surgery you are left with swelling, and quite often, scar tissue. The latter may or may not go away. If it settles in a bad place, it can make your nose look wonky. Or if in the tip, make it look big. I was left with scar tissue, in my tip, but generally speaking my nose is much better than it was before. So it was worth it. Just keep your expectations realistic, and make you sure you see a number of surgeons before you settle on one. It's not necessarily wise to go with the first one you see.
Hope this helps, sorry it was so long and rambling! Good luck with whatever you decide to do :-)