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Well, if she is having OCD and if her mind is clouded with repetitive thoughts and ideas of obsessions then sooner or later she will start experiencing extreme degree of distress and inability to function at the highest level as per her desires both in personal and professional domains of life. So you can tell her that there is treatment available for her OCD so all she needs to do is that she needs to first accept that she is having a problem and thereafter she can pursue treatment in the form of Therapy such as Exposure Response Prevention therapy which is type of CBT counseling technique that will enable her to curb her obsessive thoughts and urges and help her to control her thoughts from getting distracted and bring in tranquility and stability to her thought process.
In addition to the therapy above, a combination of ssri anti depressant drug such as zoloft or lexapro and an anxiolytic drug like klonopin or ativan can be extremely useful in providing her faster relief from her OCD .
So what you can do is that you can at least try her to get started on either therapy or medications, whichever she is more comfortable in trying. You may tell her that she should get professional help because the more delay she does in getting help the more stubborn the condition will become and it will be more difficult then to manage thus taking far more time to control her obsessive thinking.
You may even show her this conversation so as to help her see where she is heading to and how she can overcome this condition and more importantly to generate insight aka awareness about her own condition which she is choosing to ignore citing reasons of being able to overcome it on her own but this is unnecessarily wasting time which she can use to start on proper treatment.
After doing as much as I have described here, if she is still not convinced by you and she feels reluctant to start on treatment then in this case you may have to take help of someone whom she trusts the most and through this person's help you may try to convince her. If this is not possible then you will have to wait for her to decide on this which will happen when her OCD becomes severe enough to cause gross decompensation that it takes away her quality of life, it will be unfortunate but you shall have no other choice but to wait for her acceptance of her condition although time and again you may tell her that help is available forher , so she just nneeds to give her nod to it.
I hope this gives you some perspective and helps you to encourage her for seeking professional help.
Wish you all the best.
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