I would wait and watch. You should know inside of a few hours which way this is going to go. The first signs are lameness, trouble with the legs. When this happened to a chick of mine that was a similar age as yours, the damage progressed very quickly.
The chick tried to come to me and collapsed at my feet, unable to stand. It quickly progressed to overall motor system malfunction, trouble breathing, and couldn't stand or even move. I euthanized as soon as I saw the chick had irreversible neurological damage. To say it was heart breaking doesn't even begin to describe the grief when such a thing happens.