Is it possible to have permanent blurry vision after a mullerectomy?

It would be unusual to  have significant blurring at 12 days post op.  If you are using any ointment then that could definitely be the reason.  If no ointment, in some people there can be a change in the shape of the eye, but this would produce some mild blurring.  See your doctor  to have them take a look and check your vision.

I think it is appropriate to bing this concern to your surgeon's attention.  You need to have a careful assessment regarding your vision.  It is important to be assessed to determine why you are having a vision issue.  If the surgeon will not assess you, please see your general ophthalmologist.