I'm glad to hear that it's doing better. What do you have on the bottom of your incubator? Grippy shelf liner can go a long ways towards preventing leg issues.
It's okay to open the incubator for a few seconds to get him and any dry chicks out. I would start treatment as soon as possible.
https://www.backyardchickens.com/articles/treating-splay-leg-in-quail.78692/