What are these lines on my breasts?

Yes, they are stretch marks. I had bad stretch marks when my boobs started growing. But now they've started to fade away. They're totally normal. Stretch marks don't really ever go away. But the color does fade so you can't see them as much. You can get some creams that might help make them less noticeable.

I think that they actually will be stretch marks, although its sometimes hard to diagnose without seeing them. Obviously no one expects you to post a picture on the internet! You don't just get stretch marks if youre fat, but when parts of your body grow quicker than the skin is able to keep up with. This is especially common in breasts especially during the ages of about 12 - 18 when the body is developing. It will be due to this - your breats will have grown quicker than the skin has had time to stretch properly so has formed stretch marks. Don't worry about it, it is completely normal, but if you are worried about it or are embarrassed by them, you can rub stretch-mark cream onto them (i have heard palmers cocoa butter works quite nicely) and eventually they will fade. If you are worried, go and see your doctor.

no there not permanent, they just appear when your breasts are going. don't worry. It's normal for a girl your age.

Cut them off