Dyslexia and the GRE
Your best option is to retake the GRE under fairer conditions. If you have already sent out the current scores, you can also update your application to mention the conditions under which you took the test the first time. Currently, however, if you have taken the test multiple times, as many do, you can decide which scores are to be sent. 

But somewhere in your application materials I suspect that you also address your dyslexia and talk about why it isn't a hinderance to your success. 

I'll note, as I have in answers to other questions, that admissions is almost never just a numbers game and individuals are examined for evidence that predicts success in future study. Some places that are overwhelmed with applications may need to reduce the number of applicants considered to a reasonable number, but normally, you need to present an application that shows both the background and the work ethic to succeed. 

If you have any negative markers in your application then they need to be explained. Hopefully, the system is sensible enough that you can amend an application that requires it. But if you haven't yet applied, make sure that your materials honestly explain things that might be questioned.