Phillip, the fact that she has ear plugs makes me skeptical. I think she could have cut her eardrums, if she had a knife like this handy. The earplugs and the knife strike me as props to fit the narrative.
The reason she is able to take a step here while a man-made mask didn't do the trick is because she is maintaining this with her own willpower. Otherwise, even while blind, I think the Storm would make her see the event. Of course, that might also be a trick (convincing her subconscious that it is a trick by being able to see without eyes).
Today at church, I actually started thinking about this (one of the songs choked me up, and tears started running my mascara). I started fixating on Mays smile and the blood reminded me of tears. All of this made for an interesting sermon, as I was holding back an urge to smile. Basically, unlike the person who suicided himself, May is able to keep herself happy (defending from despair) and either naturally or purely mentally, is inducing pain and sadness to shut out the other crap from the room.
The only question remains whether May did this with her knife or her mind, but we shall figure that out.
Update: Base on what fake Bern said, we can conclude that it is not in fact as simple as cutting out her eyes.
Which means that yeah, either the Sphere mind-shifting theory is the case (she's faking), or May has some other secret, and really did cut her eyes out but only to distract from her real trick.