No, Dwight's arrow wasn't infected. If she was infected she would've started showing signs, so she's safe for now.
She'll be fine. As for the next few episodes, she may have plot armor if the intention is for her to forgive Dwight, meaning she may not die until their conflict is officially put to rest.
Of course, they could kill her as part of Daryl's character development so that he'll be the one to forgive Dwight, but that's just shitty writing.