Hi logic...Why is it sooo hard for us to tell our parents stuff? It's an age old question believe me lol!
Self harming and feelings of depression are serious...you know this and I commend you for reaching out to us for help..that takes great bravery..Well Done!
You have been given great advice from redrose and froggy..but if you feel you really Cannot tell your parents outright..here's another suggestion or two..
In the case of my stepson it was always easier for him to come to Me with his probs...I could then tackle and prepare his father for whatever was about to unfold...Sooo, I am wondering if you have a favourite aunty perhaps or a close friend of the family that you can talk openly to and explain all so that the subject can come up more delicately for your parents..eg. they could say something like "I was talking to logic the other day and he/she seems really down etc.."
The other suggestion I have is to talk to your school counsellor if this service is available to you and you feel comfortable about this..they will be able to guide you thru the process of telling your parents I am sure
Keep us posted..and take good care.