how does ocd affect the brain

Can it? I've had it for 5 years, not just in the background, fully severe and acutely crippling. I can hardly go through life, my memory and cognition are very poor, I struggle with comprehension and have difficulty thinking clearly or having conversations to people about everyday things. Like I can only narrate my ocd thoughts in my head, regular thoughts take too much brain power to think about. I have very high anxiety and depressive feelings also. I'm just worried my brain is structurally changed from this ongoing traumatic experiencs and when I'm in my late 30s or 40s it's going to evolve into neurodegenerative diseases. I want to get a brain scan done and see if everything is alright. What kind of doctor or tests would show me that?

I feel like OCD has destroyed my brain relative to where I was before it. Headaches, worse memory, brain fog, mental fatigue, etc. How scary is that. Then I think "oh it's just 'cause you're worrying about that and it's temporary" Thing is, what happens when the temporary becomes the new normal? I hate this sh**

Another way to describe it is a loss of ability to let uncomfortable thoughts flow through our minds. It's like a fire alarm going off in our heads and an urgency to work out what these thoughts mean and what we can do about them and it's the exact reason why going to talk therapy is the worst thing that someone with OCD can do.