So sorry you needed to cut again. You must have been experiencing something pretty bad to feel the need to do that.
I dont know what sort of a relationship you have with your mom but I do know and experience the mind-set of not wanting to disappoint parents - even though mine are elderly and live in a different country I still need to hide things from them. So although I understand you very well there I urge you to consider the option of telling your mom even if she experiences disappointment - after all you have experienced something really bad yourself. She may be able to give you support.
And you did go for 6 months without cutting. That is an achievement even if you cant feel good about it right now.

The scary part is I was just depressed and that's why I did it. My mom and I are close and I love her, it's just she would be upset with me I think...

You didn't accomplish nothing. I think you accomplished a lot! 6 months is great! You don't have to start all over. Just think of it as a slip up. It happens! You don't have to break your streak. You could just think of it like, "okay I went X amount of months without cutting and only had 1 slip up!"

Try not to worry about what your mom would think. It's all about what you think. You don't have to do it for her, you are doing it for you!

I also feel that you have accomplished a lot, 6 months is awesome! Great job on that! I don't think your mom would be disappointed, I think she would be upset that someone she loves is hurting themselves. She may or may not understand what your going through but try not to worry about how she would take it, that will add unwanted stress on you. Don't forget about what you have accomplished, you can do it again.

Thank you guys... I feel better about it now. I am going to vow to continue my clean streak :)

Oh no! I don't believe you ought to feel guilty or believe you have accomplished nothing. What do you think your 6 months was?? Life is a process and so is everything else:):) Take care of YOU!