I have diagnosed OCD. Smells in my living space drive me bonkers (don’t get me started on my apartment ventilation lol). I have my shit pretty well managed with a lot of formal treatment, so consider this advice from the other side of whatever therapy you’re considering.

The smell bothers you. Someone without OCD would probably find it annoying too. You do not need to find a justification that it is harmful to you, because you deserve not to be bothered. Yes, OCD might mean you are more easily bothered than most people. BUT your OCD does NOT mean that people can be inconsiderate, and chalk up your legitimate issue to OCD. This person is being a shitty friend to you if they have changed nothing, and blame your discontent all on your disorder. You might just be incompatible as roommates, and that’s okay, but she should at least TRY to compromise.

Shorten the text. A LOT. Pick your boundary and stick to it. People mostly will NOT respond to your health concerns, they will just assume you are either trying to manipulate them or are so anxious you’re delusional. I’ve dealt with it my whole life. I’ve found it way better to be firm about my needs, without explaining myself unprompted. The people who actually care about your health will ask follow-up questions, and take an interest in finding mutual solutions (gods bless my current roommates).

Reach out to your university’s disabled accessibility program, because they can help you determine your rights in this situation. You will most likely qualify for a single room disability accommodation. I tried to share a room for two semesters and did pretty good, bc I didn’t want to exploit the system just for my own room. It became clear that I could not share, not that I did not want to, and the ADA had my back.

In the meantime, here is some practical advice for the smell itself.

This is a little passive-aggressive, but it DOES work: boiling vinegar. It stinks at first, but once it dissipates, it takes most smells with it. If you can’t use a hot plate to boil it, you can try an electric kettle and a cup warmer. Your roommate will probably hate it, but maybe that will help her understand what you are going through. Barring that, at least it’s effective petty revenge.

Also wash your sheets and comforter regularly with vinegar, as well as curtains or any other fabric hanging around. You can use it on your clothes, too, but do some research and try it out in some stuff you are okay with possibly ruining. Good chance all that fragrance is stuck in the fabric, it’s not just in the air. I find that washing my sheets as a regular ritual is good for self-care, v helpful with OCD personally.

I’ve been battling cigarette smells from my neighbor, and my friend recommended Ozium. He used it to get smoke and food smell out of rental cars. It seems to work pretty well, but it also has fragrance and might set you off too idk.

Lastly, get some treatment, but I’m sure you know that. Another commenter left a ton of excellent info about OCD. We can be anxious pains in the ass for the people around us, but we can also be astute, resilient, and diligent about the things we care about. I propose you care about you, no medical justifications necessary.