[Jess~]

First of all, it is definitely not your fault. Yeah, you have dyslexia, okay. But the fact that you have that isn't your fault, so how can it truly be your fault that it affected you at that moment? If you get another tattoo in the future, ask them to read it out loud to you so you can be sure.

I struggle a lot with tormenting myself over the things I don't physically like about myself, and one tip my counselor tells me to practice is to look in the mirror (or in your case, at the tattoo) and notice the bad thing, but also recognize the good around it. Like "Yeah my nose is big, but look at those eyes."
So in your case, acknowledge that the mistake bothers you, but also look at the beautiful, cool parts of the tattoo. Like how much you like the font, or the designs around it.
Even with the mistake, it makes sense, though I definitely understand why you're so upset. I don't often recommend this, but perhaps keeping in mind that it could've been worse would help? Like at least nothing is mispelled or messed up in any other aspects. I know that's not the greatest help, but all you can do at this point is accept it or try to get it removed and redone.