Tiny line shaped indentation around hair folicle on breast, 26, in the process of getting diagnosed with PCOS.

[Nonoanddefintelyno]

Is literally no more than a milmetre in length. Its right next to a hair follicle but this is literally causing me to ruminate on being convinced that I have breast cancer at the age of 26. I dont think I can feel an obvious lump but my breasts are very textured and rope-like/dense breast tissue so it's hard to find what's actually a lump and what's just normal textured breast tissue for me

Obviously no one can tell you for certain and you have to make your own decisions about whether you’re right to be worried and when to seek medical advice. However, what you describe here sounds a bit like an ingrown boob hair. It might be worth thinking along those lines and having a good look. If you think it is a hair, you can usually get them out with a pin and pair of tweezers without doing yourself too much damage. If not, just go to the GP and set your mind at rest.

Please see your GP, I’ve said this before but it sounds like health anxiety, you need to be checked to put your mind at rest and then get some help for the anxiety. No one on here can tell you if you’ve got cancer, no matter how many times you ask. Please see your GP.

I second what @CuckooLaLa is saying above. Honestly. This is not a rational fear that you have. I have PCOS so I understand it can raise your risk of certain health conditions but breast cancer isn't even one of them.
Get to the GP and have a chat about your anxiety. It will help you WAY more than posting on forums