Can Hyaluronidase injection cause scleral thinning or changing color of the sclera? Please, this is very important to me!

I am sorry to hear about the trouble you are having after your injections.  Hyaluronidase is used in local anesthetic injections which are delivered around and behind the eye on a frequent basis. I just attended a corporate advisory board in which experts in the use of hyaluronidase shared their experience and can assure you that this drug has not been reported in the medical literature to cause thinning of the sclera. 

I am unaware of this association.  Color change of the iris (not the sclera) is associated rarely with Latisse.  I am obviously sorry for the problems you're having but, to the best of my knowledge, they are unrelated to either the HA treatment, or to the hyaluronidase.I hope that this helps, and good luck,Dr. Alan EnglerMember of RealSelf100

If your hyaluronidase was injected into your NLF lines and marionette
lines it would have zero ability to travel to your eyes and affect your
sclera. Not possible. The stinging and redness is because your injection
was done without lidocaine (which means it hurt badly), and then it was
irritated from the pain. It's silly not to use lidocaine along with
hyaluronidase though some people do inject it this way. But no, your
sclera issues have nothing to do with your injections. "This answer has been solicited without seeing this patient and
cannot be held as true medical advice, but only opinion. Seek in-person
treatment with a trained medical professional for appropriate care."