What do you do if you're a 14 year old transsexual guy and your parents don't know about it and need help getting clothes and make-up without them knowing when everyone in your town knows you?

You can't. Go somewhere else or just let them judge you. If you know everybody then they will know.

If you had trusted friends, they might could help. Some of your female friends could shop for you. Or maybe you could try mail order. If nothing else, have the packages sent to another address. However, the best advice in this might be to tell your parents.