I would say that anything is possible. For example. they say that some people with Autism can become more sensitive as they grow older, before eventually becoming deaf due to age.
I am much more hypersensitive to sound than i used to be. I believe that when i was younger, say during my early teen age years, my testosterone was high, and i lived in a fairly low sensory area. So noise sensitivity didn't upset me as much as it did when i grew older.
When i grew older, my testosterone dropped to major low levels (which can cause depression in itself, and depression, if left untreated leads to brain damage, which also then causes anxiety)... Anxiety and depression both can cause brain fog.
Hormonal levels can cause brain fog.
Some vitamin and mineral deficiencies can cause brain fog. (B12 deficiency can make you super tired)
Dehydration can cause brain fog.
So there are all sorts of possible causes to cognitive dysfunction.
Although i am no neural scientist, i would say that if brain damage occurs to the part of the brain that deals with short term memory and or linguistic and written communication, then sure. it is possible that you can become dyslexic, although generally speaking it isn't generally a consideration.
If i were you I would consider doing the following:
Get a hormone, diabetes, vitamin and mineral blood tests from you doctor.
Identify any deficiencies and resolve them.
Rehydrate, perhaps with rehydration salts. and or isotonic drinks.
Get a good nights sleep.
See how you feel then.